The metro in one view
Northern Virginia is the single largest cluster in the atlas. The 95 facilities recorded here are 7% of the 1,331 United States facilities in the catalogue, packed into nine places across four counties: Ashburn, Sterling, Leesburg and Culpeper to the west, Manassas and Gainesville to the south, and Reston, Herndon and Chantilly along the corridor towards Washington. Ashburn carries most of the weight on its own, with 53 facilities, followed by Sterling with 15 and Manassas with 9. That concentration is why the area is known as Data Center Alley, and why the decisions of a handful of county boards now matter to cloud capacity far beyond Virginia.
The stock is mature. 84 of the 95 facilities are operating, and only 12% of the metro’s records are still under construction or announced. 28 operators run sites here, but the market is led by a few names: the three largest by number of facilities hold 40% of all records, with Equinix first on 16 sites and Digital Realty close behind on 15.
Operating capacity, and what it hides
38 of the operating facilities publish a power figure, and together they add up to 2,753.7 MW. The median published size of an operating building is 39 MW, and the largest operating figure in the metro belongs to STACK NVA02, run by STACK Infrastructure, at 420 MW.
Those totals understate the market, and the reason is visible in the operators table. The two companies with the most sites, Equinix and Digital Realty, publish no per-building capacity in the sources the atlas uses, so their 16 and 15 facilities contribute nothing to the megawatt total. The published megawatts come mostly from wholesale and hyperscale-oriented developers that market buildings by capacity: STACK Infrastructure with 875 MW across 5 sites, Vantage Data Centers with 590 MW, QTS with 274 MW, DataBank with 261.9 MW and CyrusOne with 233 MW. Read the MW column as a floor set by who chooses to publish, not as the size of the market.
The pipeline is moving out of Ashburn
9 projects are under construction, 9 of them with a published figure adding up to 1,125 MW, and 2 more are announced with 268 MW between them. The median size of a building under construction is 96 MW, more than double the operating median, so each new project adds far more capacity than the buildings that made the alley’s name.
The geography of the pipeline is the more telling change. Ashburn, with 53 facilities, has only 2 projects in the pipeline. The rest are in Sterling (3), Gainesville (2), Leesburg (2), Manassas (1) and Culpeper (1). The largest projects show the same drift: Corscale’s Gainesville Crossing campus at 326 MW in Prince William County, Vantage’s third Ashburn campus at 288 MW, and EdgeCore’s announced Culpeper campus at 196 MW, two counties away from where the cluster began.
From by-right to a pause
The rules recorded for Northern Virginia explain much of that drift. The atlas holds 5 measures for the metro’s counties, and read in order they show a steady narrowing of what can be built without a public vote.
The first constraint was power. In July 2022 Dominion Energy told operators that transmission limits meant it could not guarantee connections for new data centers in eastern Loudoun County. It lifted the pause that September but warned that some planned projects would face delivery limits until 2026. Zoning followed. Fairfax County adopted stricter standards in September 2024, with minimum distances from homes and Metro stations, generator setbacks and noise studies. In March 2025 Loudoun County removed by-right data center development altogether, so every proposal now needs a planning commission hearing and a board vote; applications filed before 12 February 2025 were grandfathered if they sit more than 500 feet from homes.
In September 2026 the brakes tightened on both sides of the metro. Loudoun supervisors voted for a 12-month pause on new data center applications while the county rewrites its regulations, and Prince William County ended by-right development countywide, shrinking its data center overlay district and requiring a special use permit outside it. Projects already built, under construction or holding approved site plans were given a grace period. The practical effect is visible in the tables: the projects already under construction will be finished, but new proposals in the two largest counties face a public process that did not exist three years ago, which pushes developers towards Culpeper and further afield.
Cooling, AI and water
Liquid cooling is recorded at 7 Northern Virginia facilities, and 10 are flagged as AI-ready in their source documents. Both numbers are small against the size of the metro, because most of the stock was designed for conventional cloud and enterprise loads before dense accelerator racks arrived.
Water is a local question here as much as in desert markets. Loudoun County reports that on an average day data centers account for 9% of the county’s potable water use, and that Loudoun Water’s reclaimed water system delivered more than 750 million gallons to roughly 40 customers in 2025, much of it for cooling. How much water data centers use, and why, is covered in the guide how much water does a data center use.
Reading these tables
Every row below comes from the atlas catalogue, with a source for each facility listed on the Sources page. 31 of the 95 facilities have published coordinates and appear on the map above; the rest are placed by city only. The catalogue is not a census of every server room in the region: it is strongest for colocation, wholesale and hyperscale campuses and thinner for private enterprise sites. Megawatts are the figures operators and developers published, without conversion between IT load and grid connection. The same records appear on the projects tracker and the interactive map.