St. Mary's County, Maryland: Power, Data Centers and the Local Economy
Home to Leonardtown
No data center or power plant project is on record in St. Mary's County, but the national build-out still reaches it through its utility bill, its labor market and the projects next door. St. Mary's County is home to Leonardtown. Construction employs 2,151, up 16.8% since 2019. Next door, Charles County has 1 data center. Employers here counted 47,919 jobs in 2025, up 4.7% from 2019 (the 6th fastest growth of 24 Maryland counties). Electrical contractors employ 585, at an average $99,050 a year.
Cities and towns in St. Mary's County
St. Mary's County is home to Leonardtown.
Unincorporated communities (governed by the county): California, Callaway, Charlotte Hall, Golden Beach, Lexington Park, Mechanicsville, Piney Point, St. George Island, Tall Timbers, Wildewood.
Residents are 2025 Census estimates for the part of each city, town or township inside this county. Census publishes no annual estimate for unincorporated communities.
What changed in St. Mary's County
1st = the most. Ranks cover counties with a value on record.
| Measure | Then | Now | Change | Rank in Maryland |
|---|---|---|---|---|
| Population (2020 → 2025) | 113,992 | 116,692 | ▲ 2.4% | 12th of 24 by size |
| Total jobs (2019 → 2025) | 45,789 | 47,919 | ▲ 4.7% | 6th of 24 by growth |
| Average annual pay (2019 → 2025) | $69,225 | $87,584 | ▲ 26.5% | — |
| Construction jobs (2019 → 2025) | 1,842 | 2,151 | ▲ 16.8% | 3rd of 15 by growth |
| Unemployment rate (2019 → August 2026) | 3.1% | 3.7% | ▲ 0.6pts | — |
Unemployment was 3.7% in August 2026, against 3.1% in 2019. Southern Maryland Elec Coop Inc is the largest utility serving St. Mary's County. Its residential customers paid an average 14.84¢/kWh in 2024. 116,692 people live here, up 2.4% since 2020.
Who powers St. Mary's County
Utilities with service territory in St. Mary's County
| Utility | Ownership | Service | Residential customers (systemwide) | Residential price, 2024 | Commercial share of sales |
|---|---|---|---|---|---|
| Southern Maryland Elec Coop Inc | Cooperative | Bundled | 160,882 | 14.84¢ | 36% |
Customer counts, prices and sales shares cover each utility's whole system in the state, not only this county. Commercial sales include data centers.
No operating power plant is located in St. Mary's County in the EIA-860M inventory. Its power comes over the grid from plants elsewhere.
The St. Mary's County labor market
| Industry (2025) | Jobs | Average pay | Concentration vs U.S. |
|---|---|---|---|
| All industries | 47,919 | $87,584 | 1.00 |
| Construction | 2,151 | $79,774 | 0.85 |
| Electrical contractors | 585 | $99,050 | 1.69 |
Concentration is the BLS location quotient: 1.0 means the industry holds the same share of local jobs as it does nationally. Industry rows count private employers; cells BLS suppresses are left out.
Data centers and local rules in St. Mary's County
No data center, local measure or delayed project is on record in St. Mary's County. Maryland has 31 local measures on record statewide, and 1 neighboring county has one: Calvert County.
St. Mary's County and its neighbors
Of the 2 counties that border St. Mary's County, Calvert County carries the most build-out activity: data centers, planned generation and operating plants combined.
| County | Population | Jobs since 2019 | Operating MW | Planned MW | Data centers | Local measures |
|---|---|---|---|---|---|---|
| St. Mary's County | 116,692 | ▲ 4.7% | — | — | — | — |
| Calvert County | 94,484 | ▼ 0.6% | 1,852 MW | — | — | 1 |
| Charles County | 176,593 | ▲ 4.9% | 1,079 MW | — | 1 | — |
More of Maryland
St. Mary's County, answered from the record
Who provides electricity in St. Mary's County, Maryland?
1 utility has service territory in St. Mary's County in the EIA-861 2024 report: Southern Maryland Elec Coop Inc. The largest, Southern Maryland Elec Coop Inc, charged residential customers 14.84¢/kWh on average in 2024.
Are there data centers in St. Mary's County?
The SAVRN Data Center Map has no data center in St. Mary's County. The nearest activity on record is next door in Charles County.
Is St. Mary's County adding jobs?
Employers counted 47,919 jobs in 2025 against 45,789 in 2019 (+4.7%, BLS QCEW). Construction went from 1,842 to 2,151.
Does St. Mary's County have a data center moratorium?
No county-level measure is on record for St. Mary's County. Maryland has 31 local measures statewide, listed on the state page.