How many hydroelectric power plants are in Maryland?

2, with 551 MW of nameplate capacity between them, spread over 2 counties. That is the EIA-860M operating count for 2026-07.

Is there a map of Maryland hydroelectric power plants?

Yes — the map above. Each dot is one hydroelectric power plant, sized by nameplate capacity and placed at the coordinates EIA files for it.

Which is the largest hydroelectric power plant in Maryland?

Conowingo, at 531 MW. The table is sorted largest first, so the rest follow it.

Is there a hydroelectric power plant near me in Maryland?

The county roll-up below groups every plant by county, which is the quickest way to find the one closest to a given town.

Which grid operator runs Maryland's hydroelectric power plants?

Most of them sit inside PJM, according to the balancing-authority code EIA files against each plant. Live conditions for that market are on this site.

How current is this, and what is left out?

EIA-860M for 2026-07. Conventional hydroelectric. Pumped storage is counted separately. Plants below 1 MW are not surveyed by EIA and so are absent; retirements and additions after 2026-07 arrive with the next monthly release.

Hydroelectric Power Plants in Maryland

Every operating hydroelectric power plant in Maryland on EIA-860M for 2026-07: 2 plants, 13 generating units and 551 MW of nameplate capacity across 2 counties, most of it inside PJM.

As of 2026-07 (inventory dated 2026-07-31) · EIA-860M Preliminary Monthly Electric Generator Inventory · eia.gov/…/july_generator2026.xlsx · eia.gov/…/eia860m

Plants: 2; 13 generating units
Nameplate capacity: 551 MW
Counties: 2
Grid operator: PJM; covers most of these plants

Map of hydroelectric power plants in Maryland

Every one of the 2 plants is drawn at the coordinate EIA files for it.

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Hydro · 2

List of hydroelectric power plants in Maryland

Sort by any column. Capacity is nameplate, summed across every generating unit EIA lists at the site.

hydroelectric power plants in Maryland

ConowingoConventional Hydroelectric	Constellation Power, Inc	Harford	530.8	11	1928	Operating
Deep CreekConventional Hydroelectric	BP Piney & Deep Creek LLC	Garrett	20	2	1925	Operating

Largest hydroelectric power plants in Maryland

1ConowingoHarford County, Maryland530.8 MW
2Deep CreekGarrett County, Maryland20 MW

Hydroelectric power plants by county in Maryland

The county EIA files against each plant. It is the fastest way to find the plant nearest a given town.

County	Plants	Nameplate MW
Harford	1	530.8
Garrett	1	20

Hydroelectric Power Plants in Maryland: FAQ

How many hydroelectric power plants are in Maryland?: 2, with 551 MW of nameplate capacity between them, spread over 2 counties. That is the EIA-860M operating count for 2026-07.
Is there a map of Maryland hydroelectric power plants?: Yes — the map above. Each dot is one hydroelectric power plant, sized by nameplate capacity and placed at the coordinates EIA files for it.
Which is the largest hydroelectric power plant in Maryland?: Conowingo, at 531 MW. The table is sorted largest first, so the rest follow it.
Is there a hydroelectric power plant near me in Maryland?: The county roll-up below groups every plant by county, which is the quickest way to find the one closest to a given town.
Which grid operator runs Maryland's hydroelectric power plants?: Most of them sit inside PJM, according to the balancing-authority code EIA files against each plant. Live conditions for that market are on this site.
How current is this, and what is left out?: EIA-860M for 2026-07. Conventional hydroelectric. Pumped storage is counted separately. Plants below 1 MW are not surveyed by EIA and so are absent; retirements and additions after 2026-07 arrive with the next monthly release.