Data Centers in Loudoun County, Virginia

How many data centers are in Loudoun County?

Loudoun County reports that, as of March 1, 2026, it had about 233 existing data-center buildings totaling about 56.5 million square feet, counting buildings that were already built or were in various stages of construction.

The county’s page “Data Centers: The Loudoun Story” is the source for that snapshot. It also states:

• The county covers about 520 square miles and has more than 450,000 residents.
• The average existing building is about 234,000 square feet; permits issued since 2023 point to new buildings averaging closer to 339,000 square feet.
• Most built data centers in the county went up between 2019 and 2024.
• The county issued building permits for more than 10 million square feet of data-center space in 2025, its highest one-year total.
• From 2022 to May 2026, the Board of Supervisors approved 32 of 39 legislative applications for data centers.
• About 35.7 million square feet of data-center use had been approved but not yet built (approved legislative applications, approved site plans without building permits, and site plans in review). The county says it does not expect all of that space to be constructed and that the total may shrink during later review. Based on site plans, staff estimated that 35.7 million square feet could amount to about 115 additional buildings.
• Twenty-one legislative applications, representing about 56 buildings and 20.7 million square feet, were still in process and subject to revision or a Board vote.
• More than 17,000 direct and indirect data-center-related jobs have been created, according to the county.
• Data centers accounted for 39% of the county’s overall budget in Fiscal Year 2026 through real and personal property tax revenue. The FY 2027 adopted budget projects a 40% share.

A companion table by election district, prepared by the Department of Planning and Zoning and dated August 28, 2026, breaks the March 1, 2026 snapshot down further. Countywide it shows 233 buildings and 56,540,000 square feet built or under construction. Sterling District had the largest share of that existing stock (104 buildings; 24,915,000 square feet), followed by Broad Run (63 buildings; 15,180,000 square feet). Algonkian and Catoctin showed zero buildings in that built-or-under-construction row.

The district table includes notes warning that square footage is rounded, that building counts on approved but unbuilt parcels are estimates, and that the county does not warrant the data as complete. Use it as the county’s best public snapshot, then open the individual case.

Why is Loudoun called Data Center Alley?

Loudoun is called Data Center Alley because early internet exchange points and company headquarters pulled a dense web of fiber into Ashburn, and later zoning treated data centers like office buildings, which let the industry grow next to other suburban uses.

The county’s own narrative starts in the 1990s with MAE East, a commercial internet exchange near the county, and with America Online opening its global headquarters in Ashburn in 1996, followed by UUNet in 1998. In 2000, the zoning administrator determined that data centers would be regulated like offices and could be built by right wherever offices were allowed. After housing-tax revenue fell in the 2008 recession, the county leaned on the industry to diversify its tax base. MAE East later shut down, and traffic shifted toward other exchanges, including one operated by Equinix; the county says several other exchanges have since located there and that Ashburn became a uniquely connected place for data centers.

That history explains the land-use pattern residents still see: data centers mixed with commercial, light industrial, and residential areas, because office parks had already been planned near neighborhoods.

What has the county changed about approvals and hearings?

The county has moved most new data centers off the old by-right path, so a later proposal generally needs a special exception, a public hearing, and a Board of Supervisors vote.

After a 2023 zoning-ordinance rewrite, the Board started a deeper review of data-center standards and locations. In 2025 it ended by-right development of most data centers. A grandfathering resolution let certain pending applications continue on the older path. New proposals, the county says, must obtain special-exception approval: a conditional allowance for a specific use on a specific property, considered at a public hearing and then approved or denied by the Board.

A second phase of the Data Center Standards and Locations project is underway. The county expects to finish that work in spring or summer of 2027. Until then, residents should check each case for whether it is a grandfathered administrative plan or a legislative special exception.

Meetings and application materials are handled through county planning and the Board of Supervisors. The Government Center is at 1 Harrison Street SE, Leesburg, Virginia 20175; the main government number published on the county page is 703-777-0100. Case files and agendas are the documents that control a hearing, not this website.

What do data centers mean for Loudoun residents?

Data centers mean a large share of local tax revenue and employment for the county government, and they also mean resident concerns about water, noise, air quality, appearance, land values, and the electric infrastructure needed to keep adding load.

Those two facts sit next to each other in the county’s own overview. The same page that reports the budget share and job counts also says officials began looking for better ways to manage development as density increased. It lists the need for more electric transmission and distribution, substations, battery storage, and on-site generation, and it says the county is trying to diversify the commercial tax base so that it does not depend too heavily on one industry.

This site does not have an independent Loudoun water-withdrawal total that would meet the same standard as the county’s building counts, so it will not invent one. For how researchers measure data-center water and electricity nationally, see water use and electricity bills. Virginia’s State Corporation Commission has, separately, created a large-load rate class for Dominion Energy Virginia customers demanding 25 megawatts or more, effective January 1, 2027, with minimum demand charges intended to insulate other ratepayers from some infrastructure costs. That state-utility decision is not a Loudoun zoning rule, but it is part of the electric-bill context for much of northern Virginia.

If a new building is proposed near you, the questions to ask still apply: power, water, generators, noise, setbacks, and whether the case is legislative or administrative.

How can I follow a Loudoun data center application?

You can follow a Loudoun data center application by searching the county’s land-management records for the parcel or applicant, reading Planning Commission and Board of Supervisors agendas, and confirming whether the case is a special exception that will have a public hearing.

Practical steps:

1. Get the address or parcel number and search county planning / LandMARC records for the active site plan or legislative application.
2. Read the staff report for requested square footage, conditions, and whether the case is grandfathered by-right work or a special exception.
3. Watch Planning Commission and Board of Supervisors calendars for public hearings. Special-exception cases are supposed to include a hearing before the Board votes.
4. Use the county’s district table if you want to see how much existing or approved space sits in your election district, remembering that those rows are a snapshot as of March 1, 2026.
5. For transmission lines or substations, look beyond zoning to the utility and the State Corporation Commission.

The county’s data-center pages and fact sheet are updated by staff. If a number on this page disagrees with a later county publication, the county publication controls.

What are the most common questions about data centers in Loudoun County?

Does “233 buildings” mean 233 separate companies?

No. It is a building count. One campus or one operator can occupy several buildings, and square footage varies widely.

If square footage is already approved, will those buildings definitely be built?

Not according to the county. Loudoun states that it does not expect all approved but unbuilt space to be constructed.

Can a data center still be built near homes?

Yes, in the sense that older by-right projects and mixed office-park patterns already placed some halls near residential areas. New legislative cases are supposed to go through public hearings, which is the opportunity to ask about setbacks and noise.

Is Loudoun’s tax revenue from data centers a reason residents cannot ask questions?

No. Budget importance and neighborhood impacts can both be true. Questions about water, power lines, and hearings remain in order.

Is this page an official county notice?

No. It restates figures the county has already published so that residents can find them in one place. For a live case, use the county file. This page is not legal advice.

Sources

• Loudoun County, Virginia, “Data Centers: The Loudoun Story,” including the March 1, 2026 “by the numbers” section.
• Loudoun County Department of Planning and Zoning, “Data Center Buildings and Square Footage by Election District and Status, as of March 1, 2026” (table created August 28, 2026).
• Loudoun County, “Data Center Fact Sheet.”
• Virginia State Corporation Commission, November 25, 2025 biennial-review news release, case PUR-2025-00058.

County data can change after new permits or board votes. This site is not affiliated with Loudoun County or with any data-center operator. Related pages: the U.S. map, proposed projects, and questions to ask.