HELIOSOpen AI Infrastructure Observatory
Static snapshot. This site serves two different things: 1,853 data centres reported by OpenStreetMap contributors nationwide, and 13 sites Helios infers from Arizona parcel records, exported on July 29, 2026. The first is a map of what has been recorded; the second is an argued hypothesis with an evidence chain. This is a point-in-time export, not a live view. See meta.json or the methodology.

Fairfax County

County in VA · 33 data centres recorded in OpenStreetMap

Mapped facilities
33
on the map today
Floor area
0.24
km² across 31 buildings
Share of US load
262
MW, inferred upper bound
Water
0.57
million gal/day, inferred

When these appeared on the map

observed, not surveyed
01632201620182019202020212023202420252026
Data centres recorded in OpenStreetMap at the end of each month. The hatched stretch is before 2017-01, when telecom=data_center was not yet in common use — the near-zero readings there describe the tag, not the country. This is a count of what has been mapped, and OpenStreetMap carries no construction dates.
1 of these 33 facilities do not appear in the curve. The chart counts facilities whose appearance was observed in OpenStreetMap's edit history; one mapped before 2012 has no creation edit to observe. The two numbers answer different questions — how many are on the map now, and how many were watched arriving — and neither is wrong.

What the grid here looks like

reported by OSM contributors
Substations
47
69 kV and above
Bulk substations
44
230 kV and above
Highest voltage
500
kV, present in this county
Generating capacity
132
MW across 4 plants

A facility drawing hundreds of megawatts connects at bulk transmission voltage, so the second figure matters more than the first: forty 69 kV yards are not a substitute for one 500 kV substation. 1 of the plants here carry no capacity tag, so the megawatt total is a floor rather than the region's output.

Proximity is not connection. Nothing here shows that any facility has contracted power from any of these substations. That gets settled in interconnection filings Helios cannot read, and in several regions those queues now run for years. A county showing no substations may have none mapped rather than none standing.

Largest named mapped records

by mapped area
NameOperatorMapped asMapped area m²Share MWFirst mapped
CoreSite Reston VA3CoreSiteBuilding23,19925.42024-12-22
CoreSite Reston Campus VA1CoreSiteBuilding12,82414.12023-01-21
Amazon IAD-165Amazon Web ServicesBuilding12,58613.82025-09-02
Amazon IAD-167Amazon Web ServicesBuilding12,33313.52025-09-02
Amazon IAD-500Amazon Web ServicesBuilding12,24213.42025-09-02
Amazon IAD-166Amazon Web ServicesBuilding12,11613.32025-09-02
Amazon Web ServicesAmazon Web ServicesBuilding11,31512.4before 2012
Amazon Web ServicesAmazon Web ServicesBuilding11,23612.32024-02-19
Amazon Web ServicesAmazon Web ServicesBuilding11,05412.12024-02-19
Amazon IAD-168Amazon Web ServicesBuilding10,55211.62025-09-02
VA3Digital RealtyBuilding8,9419.82017-10-10
Amazon IAD-1Amazon Web ServicesBuilding8,7229.62016-12-16
Amazon IAD-9Amazon Web ServicesBuilding7,9768.72016-12-16
Equinix DC7EquinixBuilding7,4058.12024-08-20
Digital RealtyDigital RealtyBuilding6,7207.42016-12-17
Menlo Digital MD-DC1not recordedBuilding4,2024.62026-05-25
Equinix DC97EquinixBuilding4,0874.52024-12-22
Lumen McLeanLumen TechnologiesBuilding3,9074.32024-12-19
CoreSite Reston Campus VA2CoreSiteBuilding3,7644.12024-12-22
Amazon IAD22Amazon Web ServicesBuilding2,8003.12024-12-19
DataBank McLean IAD2DataBankBuilding2,1332.32024-12-19
Element Critical VA1not recordedBuilding1,9032.12024-09-09
IAD1EvocativeBuilding1,7952.02023-09-12
8100 Boone BoulevardDigital RealtyPoint——2020-10-07
Lumen McLeanLumen TechnologiesPoint——2022-04-16

“First mapped” is when OpenStreetMap recorded the facility, not when it was built — OpenStreetMap carries no construction dates. Mapped area means a building floor plate, campus boundary, or construction polygon according to the “Mapped as” column; those quantities are never added together. The megawatt column appears only for buildings and is their floor-area share of a reported national total, not a measurement.