Abstract
Northern Virginia has the largest concentration of data centers in the world, and debate over whether it can keep growing usually runs on forecasts of future demand. We instead built a facility-level inventory from county GIS records of legally entitled land, which measures the upper-bound potential of what can be built rather than a construction forecast. Loudoun and Prince William Counties have entitled 147 million square feet of data center floor area, having built approximately 49 million. At the load intensity implied by the state's own audit, the entitled total corresponds to 11,781 megawatts, 2.3 times the current load of every data center in Virginia, and to 13.2 to 14.7 million gallons of water per day, 2.3 to 2.6 times current statewide data center use. The jobs most often cited as the industry's economic benefit are primarily construction jobs that end with buildout, while resource demand lasts for each facility's life. PJM's independent market monitor attributes $16.6 billion in capacity market cost increases across two auctions to data center load. We find that data center siting regulations are active: Loudoun ended by-right data center development in 2025, and Prince William cut its data center overlay district by more than half in 2026. Every siting and water instrument in the region still applies to a single parcel or utility, and no venue evaluates the entitled total, so expansion at the entitled scale cannot be reconciled with governance as it is currently structured.