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.

MD

State · 12 data centres recorded in OpenStreetMap

Mapped facilities
12
on the map today
Floor area
0.04
km² across 7 buildings
Share of US load
44
MW, inferred upper bound
Water
0.10
million gal/day, inferred

When these appeared on the map

observed, not surveyed
0713202120212022202320232024202420252025
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.

What the grid here looks like

reported by OSM contributors
Substations
360
69 kV and above
Bulk substations
86
230 kV and above
Highest voltage
500
kV, present in this state
Generating capacity
12,624
MW across 262 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. 109 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
Lincoln Rackhouse MarylandLincoln RackhouseBuilding13,59214.92023-09-05
AiNETnot recordedBuilding4,0004.42022-11-04
TierPoint Baltimore BWInot recordedBuilding3,1003.42022-11-02
Baltimore Technology Parknot recordedBuilding2,7993.12022-11-04
Johns Hopkins Data Centernot recordedBuilding3600.42021-04-16
Crown Castle BaltimoreCrown Castle FiberPoint2022-04-16
AiNET One Market CenterAiNETPoint2022-04-16
Expedient Owings MillsExpedientPoint2023-09-04
Lumen BaltimoreLumen TechnologiesPoint2023-09-05
Expedient TidepointExpedientPoint2023-09-05

“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.