County Maps US

Frederick County, Maryland

The largest of Maryland's 24 counties by land area.

CountyFIPS 24021

Within Maryland
Frederick County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Frederick, the county seat, located via the 2025 Census Gazetteer.

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Population
302,883
+30,116 (+11.0%) since 2020
Land area
660.6
square miles. A further 1.0% of the total area is water
Population density
458
people per square mile, computed rather than published
County seat
Frederick
Seat of county government.
Established
1748
277 years ago
Largest city
Frederick city
Population 92,059.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Frederick County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Frederick County, Maryland from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 715 by 800 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Frederick County ranks

Position among the 24 counties of Maryland, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn MarylandNationally
Population302,8837th of 24245th of 3,144
Land area660.6 sq mi1st of 241,422nd of 3,144
Population density458 per sq mi8th of 24308th of 3,144
Median household income$122,0026th of 2450th of 3,143

Full data for Frederick County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population302,883Vintage 2025 Population Estimates
Population in 2020272,767Vintage 2025 Population Estimates
2020 estimates base?271,710Vintage 2025 Population Estimates
Land area660.6 sq mi2025 Gazetteer Files
Water area6.8 sq mi2025 Gazetteer Files
Total area667.4 sq mi2025 Gazetteer Files
Population density?458 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$122,002American Community Survey 2020-2024 5-Year Estimates
Median home value$464,600American Community Survey 2020-2024 5-Year Estimates
Median age39.0American Community Survey 2020-2024 5-Year Estimates
Households104,635American Community Survey 2020-2024 5-Year Estimates
Housing units108,924American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
+1,107
3,160 births, 2,053 deaths
Net migration
+2,910
More people moved in than moved out.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 7 areas bordering Frederick County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Carroll CountyMaryland47 mi176,677
Washington CountyMaryland34 mi157,731
Montgomery CountyMaryland18 mi1,074,582
Loudoun CountyVirginia16 mi449,749
Adams CountyPennsylvania13 mi107,594
Franklin CountyPennsylvania0.5 mi160,652
Howard CountyMaryland266 ft339,183

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

All 24 counties of Maryland

Open the interactive Maryland county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.