PROFFER STATEMENT
LOUDOUN COUNTY ZONING MODIFICATION APPLICATION NO. ZMOD-2025-0038
STONEBRIDGE DATA CENTER CAMPUS
May 30, 2025
Applicant: Ironhaven Data Centers LLC, a Delaware limited liability company
Property Owner (Stonebridge Parcel): Blackthorn Realty Group, Inc., a Virginia corporation
Property Owner (Meridian Parcel): Meridian Acres LLC, a Virginia limited liability company
Property Location: Northeast corner of Belmont Ridge Road and Stonebridge Boulevard, unincorporated Loudoun County, Virginia 20148
Tax Map References: Loudoun County Tax Map Ref. /95-4A-1/// (Stonebridge Parcel, 62.0 acres) Loudoun County Tax Map Ref. /95-4A-2/// (Meridian Parcel, 19.4 acres)
Total Campus Acreage: 81.4 acres
Existing Zoning: PD-IP (Planned Development – Industrial Park)
Requested Zoning Modification: ZMOD to permit data center use under the Loudoun County Zoning Ordinance
Project Name: Stonebridge Data Center Campus
Date of Proffer Statement: May 2025
Prepared by:
Ashcroft & Wynn, P.C. Thomas Ashcroft, Lead Partner 25 West Market Street Leesburg, Virginia 20176 Local Zoning Counsel for the Applicant
In coordination with:
Calderwood & Harkness LLP Douglas Fairchild, Responsible Partner 1900 K Street NW, Suite 800 Washington, DC 20006 Lead Counsel for the Applicant
Cornerstone Land Use Consulting, LLC Alan Mercer, Principal Consultant 19 Cornwall Street NW, Suite 210 Leesburg, Virginia 20176 Land Use Consultant for the Applicant
Submission Target: Loudoun County Board of Supervisors hearing, October 2025
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SECTION 1: INTRODUCTION AND PURPOSE
1.1 Purpose of the Proffer Statement
This Proffer Statement (the "Proffer Statement") is submitted voluntarily by the Applicant, Ironhaven Data Centers LLC ("IHDC" or the "Applicant"), a Delaware limited liability company, together with the property owners, Blackthorn Realty Group, Inc., a Virginia corporation (owner of the Stonebridge Parcel), and Meridian Acres LLC, a Virginia limited liability company (owner of the Meridian Parcel), in connection with Zoning Modification Application No. ZMOD-2025-0038 (the "Application"). The Application seeks approval of a zoning modification to permit data center use on the Property (as defined herein) within the existing PD-IP (Planned Development – Industrial Park) zoning classification under the Loudoun County Zoning Ordinance.
The proffers set forth herein are offered voluntarily by the Applicant and the property owners pursuant to Section 15.2-2303 of the Code of Virginia (1950), as amended, and in accordance with the applicable provisions of the Loudoun County Zoning Ordinance, as amended. These proffers are intended to address and offset the impacts on the County's public facilities, infrastructure, transportation network, and surrounding properties that are reasonably attributable to the proposed data center development on the Property.
Upon approval of the Application by the Loudoun County Board of Supervisors (the "Board"), the proffers contained in this Proffer Statement shall be binding upon the Applicant, the property owners, and their respective successors, heirs, and assigns, and shall run with the land comprising the Property as described herein. These proffers are offered in consideration of, and conditioned upon, the Board's approval of the Application as submitted or as may be modified in a manner acceptable to the Applicant and the property owners during the public hearing process.
1.2 Project Overview
IHDC proposes to develop a ground-up data center campus to be known as the "Stonebridge Data Center Campus" (the "Campus" or the "Stonebridge Campus") on the combined 81.4-acre site consisting of the Stonebridge Parcel (62.0 acres, Loudoun County Tax Map Ref. /95-4A-1///) and the Meridian Parcel (19.4 acres, Loudoun County Tax Map Ref. /95-4A-2///), situated at the northeast corner of Belmont Ridge Road and Stonebridge Boulevard in unincorporated Loudoun County, Virginia 20148.
The Campus will consist of four (4) data center buildings, designated Building A, Building B, Building C, and Building D, each designed to provide approximately 120,000 square feet of shell area and to support approximately 24 megawatts ("MW") of critical IT load capacity. In addition to the four data center buildings, the Campus will include a central utility plant, structured parking facilities, and all associated site infrastructure necessary to support the operation of a modern, enterprise-grade data center campus. The total gross floor area ("GFA") of the Campus is estimated at approximately 480,000 square feet, with a total critical IT load capacity of approximately 96 MW.
The total project budget for the Stonebridge Data Center Campus is approximately $600,000,000, representing a significant capital investment in Loudoun County and the broader Northern Virginia region.
IHDC is a Delaware limited liability company headquartered at 44680 Prentice Drive, Suite 200, Ashburn, Virginia 20147. IHDC is a portfolio company of Ridgeline Capital Partners Fund IV, LP, a private equity fund focused on digital infrastructure investments. IHDC currently operates three existing data center facilities in the Northern Virginia market, collectively providing 42 MW of critical IT load capacity to a diversified tenant base of enterprise, hyperscale, and cloud computing customers. The Stonebridge Data Center Campus represents a substantial expansion of IHDC's Northern Virginia portfolio and underscores the continued demand for high-quality, purpose-built data center capacity in the region.
Construction of the Stonebridge Data Center Campus is anticipated to commence in the fourth quarter of 2025, with a Notice to Proceed target date of November 1, 2025. The development will proceed in two phases: Phase I, consisting of Building A and the central utility plant, with a targeted substantial completion date of August 1, 2027; and Phase II, consisting of Buildings B, C, and D, with a targeted substantial completion date of November 1, 2027. The overall construction timeline encompasses an approximately 24-month construction period.
1.3 Current Zoning and Requested Modification
The Property is currently zoned PD-IP (Planned Development – Industrial Park) under the Loudoun County Zoning Ordinance, as amended. The PD-IP district is designed to accommodate a range of industrial, office, and technology-related uses in a planned development setting that encourages coordinated site design, adequate buffering, and compatible land use relationships.
The Application requests a zoning modification ("ZMOD") to permit data center use on the Property within the PD-IP zoning classification. Data center use, while consistent with the general character of the PD-IP district, requires specific authorization through the ZMOD process to ensure that the unique characteristics of data center operations—including power infrastructure, mechanical systems, noise generation, and visual impact—are appropriately addressed through the proffers and conditions of approval.
The proposed data center use is consistent with the Loudoun County Comprehensive Plan, including the policies and objectives of the applicable planning subarea, and with the County's long-standing and well-documented support for digital infrastructure investment in the western portion of Loudoun County. Loudoun County is widely recognized as a global center for data center development, and the Stonebridge Data Center Campus will further strengthen the County's position as a premier location for mission-critical digital infrastructure.
1.4 Property Owners
The Stonebridge Parcel (62.0 acres, Loudoun County Tax Map Ref. /95-4A-1///) is owned by Blackthorn Realty Group, Inc., a Virginia corporation, with its principal office located at 112 East Market Street, Suite 400, Leesburg, Virginia 20176. The President of Blackthorn Realty Group, Inc. is Donald R. Whitaker, and its General Counsel is Patricia Whitaker-Connolly.
The Meridian Parcel (19.4 acres, Loudoun County Tax Map Ref. /95-4A-2///) is owned by Meridian Acres LLC, a Virginia limited liability company, with its principal office located at 3401 Old Ox Road, Sterling, Virginia 20166. The Managing Member of Meridian Acres LLC is Theodore Ashford.
Both property owners join in this Proffer Statement as signatories hereto and hereby consent to the proffers set forth herein. Each property owner represents and warrants that it has full authority to execute this Proffer Statement and to bind the respective parcel to the obligations contained herein.
SECTION 2: DEFINITIONS
As used in this Proffer Statement, the following terms shall have the meanings set forth below unless the context otherwise requires:
"Applicant" shall mean Ironhaven Data Centers LLC, a Delaware limited liability company, and its successors and assigns.
"Application" shall mean Zoning Modification Application No. ZMOD-2025-0038, filed with Loudoun County, Virginia, in connection with the Stonebridge Data Center Campus.
"Board" shall mean the Loudoun County Board of Supervisors.
"Campus" or "Stonebridge Campus" shall mean the Stonebridge Data Center Campus, consisting of the Stonebridge Parcel and the Meridian Parcel, together with all improvements constructed thereon.
"County" shall mean Loudoun County, Virginia, including its departments, agencies, and instrumentalities, as the context requires.
"GFA" shall mean gross floor area, measured in accordance with the definition and methodology set forth in the Loudoun County Zoning Ordinance, as amended.
"Meridian Parcel" shall mean the 19.4-acre parcel of land identified as Loudoun County Tax Map Ref. /95-4A-2///, owned by Meridian Acres LLC.
"Phase I" shall mean the first phase of development of the Campus, consisting of Building A (approximately 120,000 square feet of GFA), the central utility plant, and associated site improvements.
"Phase II" shall mean the second phase of development of the Campus, consisting of Buildings B, C, and D (approximately 360,000 square feet of GFA in the aggregate), additional parking, and remaining site improvements.
"Property" shall mean the combined Stonebridge Parcel and Meridian Parcel, comprising a total of approximately 81.4 acres.
"Stonebridge Parcel" shall mean the 62.0-acre parcel of land identified as Loudoun County Tax Map Ref. /95-4A-1///, owned by Blackthorn Realty Group, Inc.
"ZMOD" shall mean the Zoning Modification Application filed in connection with the Application.
"Zoning Ordinance" shall mean the Loudoun County Zoning Ordinance, as amended from time to time.
SECTION 3: MONETARY CONTRIBUTION PROFFERS
3.1 Capital Facilities Contribution
The Applicant hereby proffers a monetary contribution to Loudoun County in the amount of Five Dollars ($5.00) per square foot of gross floor area constructed on the Property (the "Capital Facilities Contribution"). Based on the anticipated total GFA of approximately 480,000 square feet across the four data center buildings comprising the Campus, the estimated total Capital Facilities Contribution is Two Million Four Hundred Thousand Dollars ($2,400,000.00).
The Capital Facilities Contribution is intended to offset the fiscal impacts of the proposed data center development on County capital facilities, including but not limited to roads and transportation infrastructure, public safety facilities, parks and recreational facilities, and other public infrastructure that may be affected by the development of the Campus. The Applicant acknowledges that the Capital Facilities Contribution is offered voluntarily and is reasonably related to the impacts generated by the proposed development.
3.2 Phasing of Payment
The Capital Facilities Contribution shall be paid in phases corresponding to the issuance of building permits for each individual data center building, as follows:
(a) Building A: Five Dollars ($5.00) per square foot multiplied by 120,000 square feet, equaling Six Hundred Thousand Dollars ($600,000.00), payable upon issuance of the building permit for Building A;
(b) Building B: Five Dollars ($5.00) per square foot multiplied by 120,000 square feet, equaling Six Hundred Thousand Dollars ($600,000.00), payable upon issuance of the building permit for Building B;
(c) Building C: Five Dollars ($5.00) per square foot multiplied by 120,000 square feet, equaling Six Hundred Thousand Dollars ($600,000.00), payable upon issuance of the building permit for Building C;
(d) Building D: Five Dollars ($5.00) per square foot multiplied by 120,000 square feet, equaling Six Hundred Thousand Dollars ($600,000.00), payable upon issuance of the building permit for Building D;
The aggregate Capital Facilities Contribution across all four buildings shall be Two Million Four Hundred Thousand Dollars ($2,400,000.00), subject to adjustment as provided in Section 3.3 below.
3.3 Adjustment for Actual GFA
In the event that the actual GFA of any individual building differs from the estimated 120,000 square feet, the Capital Facilities Contribution for that building shall be adjusted on a per-square-foot basis at the rate of Five Dollars ($5.00) per square foot of actual GFA as shown on the approved building permit application for that building. The adjustment shall be calculated at the time of building permit issuance for the applicable building, and the payment shall reflect the actual GFA approved under the building permit.
In no event shall the aggregate Capital Facilities Contribution be less than Two Million Four Hundred Thousand Dollars ($2,400,000.00) if the total GFA of all buildings constructed on the Property equals or exceeds 480,000 square feet. If the total GFA of all buildings is less than 480,000 square feet, the aggregate contribution shall be calculated at the rate of Five Dollars ($5.00) per square foot of actual total GFA.
3.4 Payment Mechanics
All monetary proffer payments required under this Section 3 shall be made to the Loudoun County Treasurer, or to such other entity or account as may be designated by the Board or the County Administrator. Payments shall be made by certified check, cashier's check, or wire transfer of immediately available funds, as directed by the County. The Applicant shall provide written notice to the County's Department of Planning and Zoning at the time of each proffer payment, identifying the building for which the payment is made, the actual GFA of the building, and the amount of the payment.
SECTION 4: TRANSPORTATION PROFFERS
4.1 Road Improvements — Belmont Ridge Road
The Applicant hereby proffers to design, construct, or fund the following improvements to Belmont Ridge Road adjacent to the Property:
(a) A dedicated right-turn deceleration lane at the main campus entrance from Belmont Ridge Road, designed and constructed in accordance with Virginia Department of Transportation ("VDOT") standards and specifications for turn lane geometry, length, taper, and pavement markings;
(b) A dedicated left-turn lane at the main campus entrance from Belmont Ridge Road, designed and constructed in accordance with VDOT standards and specifications, subject to review and approval by VDOT. The Applicant acknowledges that VDOT review of the left-turn lane may require additional engineering analysis and that the final design, geometry, and location of the left-turn lane shall be subject to VDOT approval through the site plan and VDOT plan review process; and
(c) Widening of the existing roadway shoulder along Belmont Ridge Road as necessary to accommodate the right-turn deceleration lane and left-turn lane described above, including any associated pavement, striping, signage, and drainage improvements required by VDOT.
All road improvements described in this Section 4.1 shall be designed and constructed in accordance with the applicable standards, specifications, and requirements of the Virginia Department of Transportation, and shall be subject to VDOT review, inspection, and acceptance. The Applicant shall obtain all necessary VDOT permits and approvals prior to commencing construction of any improvements within the VDOT right-of-way.
4.2 Road Improvements — Stonebridge Boulevard
The Applicant hereby proffers to design, construct, or fund the following improvements along Stonebridge Boulevard adjacent to the Property:
(a) Widening of Stonebridge Boulevard along the Property frontage to accommodate a shared-use path or sidewalk on the campus side of Stonebridge Boulevard, in accordance with Loudoun County and VDOT design standards for shared-use paths or sidewalks, as applicable; and
(b) Any required curb, gutter, and stormwater drainage improvements associated with the road widening and shared-use path or sidewalk installation along Stonebridge Boulevard.
The design and location of the shared-use path or sidewalk shall be coordinated with the County's Department of Transportation and Capital Infrastructure and with VDOT, as applicable, to ensure consistency with planned pedestrian and bicycle facilities in the vicinity of the Property.
4.3 Traffic Impact Analysis
The Applicant has commissioned, or shall commission prior to site plan approval, a Traffic Impact Analysis ("TIA") prepared by a qualified traffic engineering firm in accordance with Loudoun County and VDOT requirements for traffic impact studies. The TIA shall evaluate the traffic impacts of the proposed data center development on the surrounding road network, including Belmont Ridge Road, Stonebridge Boulevard, and other roadways in the study area as determined by the County and VDOT.
The Applicant notes that data center facilities generate substantially lower vehicular trip generation compared to typical industrial, office, and other commercial uses on a per-square-foot basis. Data centers are characterized by low employee density, minimal visitor traffic, and limited delivery and service vehicle activity relative to the building footprint. The TIA is expected to demonstrate a net reduction in peak-hour vehicular trip generation compared to the trip generation that would result from development of the Property under the existing by-right PD-IP development entitlements.
Notwithstanding the foregoing, the Applicant shall implement any additional transportation improvements that are reasonably required as a result of the TIA findings and that are approved by VDOT and the County through the site plan review and approval process.
4.4 Construction Traffic Management Plan
Prior to the commencement of any construction activity on the Property, the Applicant shall prepare and submit to the County's Department of Transportation and Capital Infrastructure, and to VDOT as applicable, a Construction Traffic Management Plan ("CTMP"). The CTMP shall identify the following:
(a) Designated haul routes for construction vehicles, including routes to and from the Property and the locations of staging areas;
(b) Hours of construction traffic, including any proposed restrictions on the timing of heavy vehicle movements;
(c) Measures to minimize the impact of construction traffic on adjacent roadways, intersections, and residential areas during the anticipated 24-month construction period;
(d) Provisions for temporary traffic control, flagging, and signage at construction access points; and
(e) Contact information for the Applicant's construction traffic coordinator, who shall be responsible for addressing any construction traffic complaints or issues during the construction period.
The CTMP shall be subject to review and approval by the County prior to the issuance of any grading or building permits for the Property.
4.5 Timeline
The transportation improvements described in Sections 4.1 and 4.2 of this Proffer Statement shall be substantially completed prior to the issuance of the first certificate of occupancy for Building A. Based on the current project schedule, the target date for substantial completion of the transportation improvements is August 2027, coinciding with the targeted substantial completion date for Building A. In the event that the project schedule is modified, the transportation improvements shall nonetheless be substantially completed prior to the first certificate of occupancy for any building on the Property.
SECTION 5: NOISE MITIGATION PROFFERS
5.1 Noise Standards
The Applicant hereby proffers that the operation of the Stonebridge Data Center Campus, including but not limited to all mechanical equipment (HVAC systems, cooling towers, chillers, air handlers, and pumps), diesel backup generators (configured in a 2N redundancy arrangement for each building), and electrical infrastructure (transformers, switchgear, and uninterruptible power supply systems), shall comply with all applicable Loudoun County noise standards and regulations at all property boundary lines of the Property.
In addition to compliance with the County's noise standards, the Applicant proffers that continuous operational noise from mechanical equipment on the Campus shall not exceed the following levels, measured at ground level at any property boundary line of the Property:
(a) Daytime hours (7:00 a.m. to 10:00 p.m.): 55 dBA (A-weighted decibels); and
(b) Nighttime hours (10:00 p.m. to 7:00 a.m.): 50 dBA (A-weighted decibels).
Noise levels shall be measured using standard acoustical measurement procedures, including the use of calibrated sound level meters positioned at the property boundary at a height of approximately five (5) feet above grade level.
5.2 Noise Mitigation Measures
The Applicant hereby proffers to incorporate the following noise mitigation measures into the design and construction of the Stonebridge Data Center Campus:
(a) Mechanical Equipment Screening. All mechanical equipment, including cooling towers, chillers, and air handlers, shall be screened by masonry sound walls, acoustically rated barriers, or equivalent noise-attenuating enclosures on all sides facing property boundary lines or public rights-of-way. Sound walls and barriers shall be designed to achieve a minimum noise reduction of 10 dBA relative to unscreened conditions, as determined by the acoustical engineering analysis described in Section 5.3.
(b) Generator Testing Restrictions. Routine generator testing shall be limited to daytime hours on weekdays only (Monday through Friday, 9:00 a.m. to 5:00 p.m.) and shall not exceed thirty (30) minutes per generator per month. This restriction shall not apply to emergency generator operation during actual power outages or other emergency conditions, or to maintenance testing mandated by applicable building codes, fire codes, or the requirements of equipment manufacturers' warranties.
(c) Central Utility Plant Acoustic Design. The central utility plant shall be designed and constructed with acoustically rated walls and roofing materials to contain mechanical noise within the structure. The central utility plant shall incorporate sound-attenuating louvers, vibration isolation mounts for major equipment, and other acoustic design features as recommended by the qualified acoustical engineer retained by the Applicant.
5.3 Noise Study
Prior to site plan approval, the Applicant shall submit to the County's Department of Planning and Zoning a noise study (the "Noise Study") prepared by a qualified acoustical engineer licensed in the Commonwealth of Virginia. The Noise Study shall demonstrate that the design of the Campus, including all mechanical equipment, generators, and electrical infrastructure, will comply with the noise standards set forth in Section 5.1 of this Proffer Statement. The Noise Study shall identify the specific noise mitigation measures to be incorporated into the Campus design and shall include projected noise levels at all property boundary lines under normal operating conditions and during generator testing.
SECTION 6: VISUAL SCREENING AND LANDSCAPING PROFFERS
6.1 Perimeter Landscaping Buffer
The Applicant hereby proffers to install and maintain a perimeter landscaping buffer along all property boundaries of the Campus that are adjacent to public roads and non-industrial parcels, as follows:
(a) Belmont Ridge Road Frontage. A minimum fifty-foot (50') wide landscaped buffer shall be installed and maintained along the entire Belmont Ridge Road frontage of the Property. The buffer shall extend from the right-of-way line of Belmont Ridge Road inward toward the Campus improvements.
(b) Stonebridge Boulevard Frontage. A minimum thirty-five-foot (35') wide landscaped buffer shall be installed and maintained along the entire Stonebridge Boulevard frontage of the Property. The buffer shall extend from the right-of-way line of Stonebridge Boulevard inward toward the Campus improvements.
(c) All Other Property Boundaries. A minimum twenty-five-foot (25') wide landscaped buffer shall be installed and maintained along all other property boundary lines of the Property, including boundaries adjacent to non-industrial parcels or undeveloped land.
All perimeter landscaping buffers shall include a combination of the following plant materials, selected for hardiness, growth characteristics, and year-round screening effectiveness in the Northern Virginia climate zone (USDA Hardiness Zone 7a):
(i) Evergreen trees, with a minimum height of eight (8) feet at the time of planting, spaced at intervals sufficient to provide a continuous visual screen;
(ii) Deciduous canopy trees, with a minimum caliper of three (3) inches at the time of planting;
(iii) Understory plantings, including flowering trees, shrubs, and ground cover; and
(iv) Ornamental grasses and perennial plantings to provide visual interest and additional screening density.
Plant materials shall be installed at densities sufficient to provide an effective year-round visual screen within three (3) growing seasons of installation. The Applicant shall be responsible for the ongoing maintenance, replacement, and irrigation (as needed) of all perimeter landscaping buffer plantings for the life of the Campus.
6.2 Equipment and Infrastructure Screening
All ground-level mechanical equipment, generators, transformer pads, switchgear, utility infrastructure, and related appurtenances shall be screened from public view as observed from Belmont Ridge Road and Stonebridge Boulevard. This screening obligation shall also apply to the dedicated 230kV/34.5kV substation to be constructed on the Meridian Parcel, which, upon completion, will be owned and maintained by Vantage Power Cooperative.
Screening of equipment and infrastructure shall consist of one or more of the following methods:
(a) Masonry walls of architectural quality, designed to be compatible with the building materials and color palettes used on the data center buildings;
(b) Decorative fencing (such as ornamental metal or composite fencing) in combination with vegetative screening, including evergreen trees, shrubs, and other dense plantings; or
(c) Berming in combination with landscaping, where site grading and topography permit.
In all cases, screening shall extend to a minimum height of eight (8) feet or the height of the equipment being screened, whichever is greater. The Applicant shall coordinate with Vantage Power Cooperative regarding the screening of the substation to ensure that the screening design does not impair the safe operation and maintenance of the substation facilities.
6.3 Building Design Standards
The Applicant proffers that the data center buildings on the Campus shall incorporate architectural design treatments on all building facades that are visible from public roads, including Belmont Ridge Road and Stonebridge Boulevard. Such design treatments shall include, at a minimum:
(a) Variations in building materials, such as a combination of precast concrete, metal panel systems, masonry, and glass elements, to create visual interest and reduce the apparent mass of the building facades;
(b) Articulated facades, including changes in plane, recessed or projecting bays, and horizontal and vertical reveals, to break up large expanses of wall surface; and
(c) Coordinated color palettes utilizing neutral, earth-toned, or muted colors that are compatible with the surrounding landscape and built environment.
Rooftop equipment, including mechanical units, satellite dishes, and telecommunications equipment, shall be screened by parapets or purpose-designed equipment screens to the extent that such equipment is visible from public roads and adjacent properties. Parapets and equipment screens shall be designed as integral elements of the building architecture.
6.4 Lighting
All exterior lighting on the Campus shall be full-cutoff fixtures designed to minimize light trespass and glare at property boundaries and on adjacent properties. Exterior lighting shall comply with the Loudoun County outdoor lighting standards, including any applicable requirements regarding maximum illumination levels, fixture mounting heights, and shielding.
Security lighting shall be designed to provide adequate illumination for the safe operation of the Campus and the security of persons and property, without creating adverse lighting impacts on adjacent properties or public roadways. The lighting design for the Campus shall be submitted as part of the site plan application for review and approval by the County.
6.5 Signage
Campus signage shall be limited to monument-style identification signs located at the campus entrances and directional wayfinding signage located within the interior of the Campus. All signage shall comply with the Loudoun County sign regulations applicable to the PD-IP zoning district. No billboard, off-premise, or internally illuminated cabinet-style signs shall be permitted on the Property. Monument signs shall be constructed of materials compatible with the building design and shall be landscaped at the base.
SECTION 7: ENVIRONMENTAL PROFFERS
7.1 Stormwater Management
The Applicant hereby proffers to design, construct, and maintain stormwater management facilities for the Campus in full compliance with all applicable Loudoun County and Virginia Department of Environmental Quality ("DEQ") regulations, including the Virginia Stormwater Management Program ("VSMP") regulations and the Loudoun County Facility Standards Manual.
Best Management Practices ("BMPs") shall be incorporated into the stormwater management design for the Campus, including but not limited to the following:
(a) Bioretention facilities to promote natural filtration and treatment of stormwater runoff;
(b) Stormwater detention and/or retention ponds designed to attenuate peak stormwater flows and provide water quality treatment;
(c) Low-Impact Development ("LID") techniques where feasible, including permeable pavement, vegetated swales, and green infrastructure elements; and
(d) Erosion and sediment control measures during construction, in accordance with the Virginia Erosion and Sediment Control Law and Regulations.
A stormwater management facility easement and maintenance agreement shall be prepared and recorded in the Loudoun County land records prior to the issuance of the first certificate of occupancy for any building on the Property. The easement and maintenance agreement shall ensure the long-term maintenance and proper functioning of all stormwater management facilities on the Campus and shall be in a form acceptable to the County.
7.2 Environmental Remediation
The Applicant acknowledges that the Stonebridge Parcel has a history of former agricultural use, and that there is a potential for residual pesticide contamination in the northwest quadrant of the Stonebridge Parcel, encompassing an area of approximately 4.2 acres. The Applicant has retained Pendleton Environmental Associates, Inc., under the direction of Dr. Renata Volkov, Lead Environmental Scientist, to conduct Phase I and Phase II Environmental Site Assessments ("ESAs") of the Property in accordance with ASTM E1527-21 (Phase I) and ASTM E1903-19 (Phase II) standards.
The Phase I ESA is targeted for completion by June 1, 2025, and the Phase II ESA, which will include soil and groundwater sampling in the area of potential concern, is targeted for completion by July 1, 2025. The results of the ESAs will be submitted to the County and to the Virginia Department of Environmental Quality as appropriate.
The Applicant hereby proffers that, prior to the commencement of any grading, earthwork, or construction activity on any area of the Property where environmental contamination is identified through the ESA process or through subsequent investigation, the Applicant shall prepare, submit, and implement a remediation plan approved by the Virginia Department of Environmental Quality. The remediation plan shall address all identified contamination to the satisfaction of all applicable federal, state, and local regulatory requirements, including the Virginia Voluntary Remediation Program ("VRP") or other applicable cleanup program, as appropriate. No certificate of occupancy shall be issued for any building on the Property until the Applicant has demonstrated to the County that all required remediation activities have been completed or are being conducted in compliance with an approved remediation plan.
7.3 Tree Conservation
The Applicant shall comply with all applicable Loudoun County tree conservation regulations, including the requirements of the Zoning Ordinance and the Facility Standards Manual regarding the identification, protection, and conservation of existing trees on the Property. The Applicant shall submit a tree conservation plan with the site plan application for each phase of development, identifying all trees to be preserved and all trees to be removed.
Where tree removal is required to accommodate the construction of buildings, roads, parking, utilities, stormwater management facilities, or other Campus improvements, the Applicant shall provide replacement plantings in accordance with the County's tree replacement requirements. In the alternative, the Applicant may make payment to the County's tree replacement fund in an amount determined in accordance with the applicable provisions of the Zoning Ordinance, at the Applicant's election and as permitted by County regulations.
SECTION 8: FISCAL IMPACT PROFFERS
8.1 Fiscal Impact Summary
The Stonebridge Data Center Campus represents a total capital investment of approximately Six Hundred Million Dollars ($600,000,000), making it one of the most significant private capital investments in Loudoun County in the current development cycle. Data centers are widely recognized as among the highest revenue-generating land uses on a per-acre basis for Loudoun County, and the Stonebridge Campus is expected to generate substantial ongoing fiscal benefits for the County, including the following:
(a) Personal Property Tax Revenue. Under the Loudoun County data center equipment tax rate of $1.25 per $100 of assessed value, the IT equipment installed in the Campus by tenants deploying across the 96 MW of critical IT capacity is expected to generate significant annual personal property tax revenue. As tenants lease space and deploy equipment, the tax base attributable to the Campus will grow substantially over the initial years of operation.
(b) Real Property Tax Revenue. The assessed value of the improved real property comprising the Campus, including the four data center buildings, central utility plant, parking structures, and site improvements, is expected to contribute materially to the County's real property tax base.
(c) Employment-Related Taxes and Economic Activity. The Campus is expected to create approximately fifty (50) or more new permanent jobs, consistent with the employment thresholds established under the Virginia data center sales tax exemption provisions of Virginia Code Section 58.1-609.3(18). These positions are anticipated to include data center operations engineers, facility managers, security personnel, and administrative staff.
Importantly, the Stonebridge Data Center Campus will generate minimal demand on County services relative to its tax contribution. Data center operations are characterized by low population density, minimal school-age children generation, and limited demands on emergency services, parks, and other population-driven County services. The net fiscal impact of the Campus is expected to be overwhelmingly positive, with tax revenues significantly exceeding the cost of any County services attributable to the development.
8.2 Additional Fiscal Benefits
In addition to the ongoing tax revenues described in Section 8.1, the Stonebridge Data Center Campus will generate substantial additional fiscal and economic benefits for Loudoun County and the surrounding region, including the following:
(a) Construction Period Economic Activity. The 24-month construction period, anticipated to extend from approximately November 2025 through November 2027, will be conducted under a $412,000,000 engineering, procurement, and construction ("EPC") contract with Titan-McAllister Construction Group, LLC. The construction of the Campus will generate substantial local economic activity, including construction employment (with peak construction workforce levels expected to exceed 500 workers), local materials procurement, subcontractor engagement, and demand for related services such as lodging, food service, and transportation.
(b) Annual Utility Expenditures. The Campus's estimated annual utility demand charges are approximately Twelve Million One Hundred Twenty-Four Thousand Eight Hundred Dollars ($12,124,800), calculated based on the contracted demand of 120,000 kW at the applicable demand rate of $8.42 per kW per month, multiplied by twelve (12) months. These utility payments will be made to Vantage Power Cooperative, supporting the financial stability and operational capacity of the local utility cooperative. Additional utility costs for energy consumption, water, and sewer services will further contribute to the local utility revenue base.
SECTION 9: UTILITY AND INFRASTRUCTURE PROFFERS
9.1 Power Infrastructure
The Applicant hereby proffers to fund a line extension contribution in the amount of Eighteen Million Five Hundred Thousand Dollars ($18,500,000) to Vantage Power Cooperative ("VPC") for the design and construction of a dedicated power line extension and a 230kV/34.5kV step-down substation on the Meridian Parcel. The substation will serve the Campus's contracted electrical demand of 120 megavolt-amperes ("MVA") and will be designed and constructed by VPC or its designated contractors in accordance with VPC's engineering standards and applicable regulatory requirements. Upon completion, the substation and associated power line extension infrastructure will be owned, operated, and maintained by VPC.
The Applicant's private electrical infrastructure, including medium-voltage switchgear, step-down transformers, distribution switchboards, and electrical distribution systems within the Campus, will be designed, constructed, and maintained by the Applicant as part of the Campus's internal power infrastructure. The design and construction of the Applicant's private electrical infrastructure will be funded from the Campus's project budget and will not require any County funding or contribution.
9.2 Water and Sewer
The Applicant shall connect to Loudoun Water (or the applicable utility authority having jurisdiction) for domestic water supply and sanitary sewer service to the Campus. The Applicant shall obtain all necessary utility connections, permits, and approvals from Loudoun Water and shall fund any required line extensions, connection fees, or availability charges in accordance with Loudoun Water's applicable fee schedules and policies.
Data center water usage for cooling is expected to be moderate and consistent with industry-standard cooling technologies employed in modern data center facilities. The Applicant shall implement water-efficient cooling systems where practicable, including but not limited to air-side economization, high-efficiency chilled water systems, and closed-loop cooling configurations, to minimize water consumption and reduce the demand on the public water supply system.
9.3 Telecommunications
The Applicant shall install redundant fiber-optic telecommunications infrastructure to serve the Campus, connecting to multiple carrier meet-me points and telecommunications hubs consistent with the requirements of a Tier III or higher data center facility. The telecommunications infrastructure shall be designed to provide diverse routing and physical path separation to ensure the reliability and redundancy necessary for mission-critical data center operations.
All telecommunications lines within the Campus and along public road frontages adjacent to the Property shall be installed underground. No aerial telecommunications lines shall be constructed on the Property or along the Property's frontage on Belmont Ridge Road or Stonebridge Boulevard.
SECTION 10: PHASING
10.1 Development Phasing Plan
The development of the Stonebridge Data Center Campus shall proceed in two phases, as follows:
(a) Phase I. Phase I shall consist of the construction of Building A (approximately 120,000 square feet of GFA, with 24 MW of critical IT load capacity), the central utility plant, primary site civil improvements (including grading, utilities, stormwater management facilities, and access roads), campus entrance improvements on Belmont Ridge Road and Stonebridge Boulevard, and initial structured parking facilities. The targeted substantial completion date for Phase I is August 1, 2027.
(b) Phase II. Phase II shall consist of the construction of Building B, Building C, and Building D (each approximately 120,000 square feet of GFA, with 24 MW of critical IT load capacity per building, for a total Phase II GFA of approximately 360,000 square feet and a total Phase II critical IT load capacity of approximately 72 MW), additional structured parking, and all remaining site improvements. The targeted substantial completion date for Phase II is November 1, 2027.
The monetary contribution proffers set forth in Section 3 shall be triggered on a per-building basis, with each payment due upon the issuance of the building permit for the applicable building, as set forth in Section 3.2 of this Proffer Statement.
10.2 Site Plan Submissions
The Applicant may, at its election, submit separate site plan applications for Phase I and Phase II, or a combined site plan application covering all four buildings and all site improvements, in accordance with the applicable procedures and requirements of the Loudoun County Zoning Ordinance and Facility Standards Manual.
All landscaping and screening proffers set forth in Section 6 of this Proffer Statement shall be installed concurrent with, or prior to, the issuance of the certificate of occupancy for each phase. In the event that seasonal conditions prevent the installation of landscaping at the time of certificate of occupancy, the Applicant shall install temporary screening measures and shall complete the permanent landscaping installation within the first available planting season, and in no event later than six (6) months following the issuance of the certificate of occupancy for the applicable phase.
SECTION 11: GENERAL PROVISIONS
11.1 Binding Effect
These proffers shall be binding upon the Applicant, Ironhaven Data Centers LLC, and the property owners, Blackthorn Realty Group, Inc. and Meridian Acres LLC, and their respective successors, heirs, assigns, and legal representatives, in perpetuity, upon the approval of the Zoning Modification Application No. ZMOD-2025-0038 by the Loudoun County Board of Supervisors. The proffers contained herein shall run with the land comprising the Property and shall be enforceable by the County of Loudoun, Virginia, through all available legal and equitable remedies, including but not limited to injunctive relief and the withholding of building permits, certificates of occupancy, and other development approvals.
11.2 Severability
If any proffer contained herein, or any portion thereof, is determined to be invalid, illegal, or unenforceable by a court of competent jurisdiction, such determination shall not affect the validity, legality, or enforceability of the remaining proffers contained in this Proffer Statement. Each proffer is intended to be severable and independent, and the invalidity of any individual proffer shall not impair or affect the remaining proffers, which shall continue in full force and effect.
11.3 Modification
These proffers may be modified, amended, or released only with the prior approval of the Loudoun County Board of Supervisors, in accordance with the procedures set forth in the Loudoun County Zoning Ordinance and Virginia Code Section 15.2-2302, as amended. No modification, amendment, or release of any proffer shall be effective unless approved by the Board and recorded in the Loudoun County land records.
11.4 County Administrator Interpretation
Minor variations from the specific numerical, dimensional, or technical requirements of these proffers may be permitted by the Loudoun County Zoning Administrator (or his or her designee), provided that such variations are consistent with the overall intent and purpose of the proffers as expressed in this Proffer Statement, and provided further that such variations do not materially alter the nature or extent of the obligations assumed by the Applicant and the property owners hereunder.
11.5 Conflict with Zoning Ordinance
In the event of any conflict or inconsistency between the provisions of these proffers and the provisions of the Loudoun County Zoning Ordinance, as amended, the more restrictive provision shall control and shall be applied to the development of the Property. Nothing in this Proffer Statement shall be construed to relieve the Applicant or the property owners from compliance with any applicable provision of the Zoning Ordinance, except to the extent that a specific proffer herein expressly provides for a more restrictive standard.
11.6 Governing Law
This Proffer Statement shall be governed by and construed in accordance with the laws of the Commonwealth of Virginia, without regard to conflicts of law principles. Any legal action or proceeding arising out of or relating to this Proffer Statement shall be brought exclusively in the Circuit Court of Loudoun County, Virginia, or, if applicable, in the federal courts having jurisdiction over Loudoun County, Virginia.