County Maps US

Delaware County, Pennsylvania

A county in Pennsylvania, ranked 5 of 67 by population.

CountyFIPS 42045

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

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Population
580,937
+4,432 (+0.8%) since 2020
Land area
183.8
square miles. A further 3.6% of the total area is water
Population density
3,161
people per square mile, computed rather than published
County seat
Media
Seat of county government.
Established
1789
236 years ago
Largest city
Chester city
Population 33,996.

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 Delaware 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 Delaware County, Pennsylvania 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 800 by 717 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 Delaware County ranks

Position among the 67 counties of Pennsylvania, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn PennsylvaniaNationally
Population580,9375th of 67123rd of 3,144
Land area183.8 sq mi65th of 673,023rd of 3,144
Population density3,161 per sq mi2nd of 6732nd of 3,144
Median household income$89,5465th of 67312th of 3,143

Full data for Delaware County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population580,937Vintage 2025 Population Estimates
Population in 2020576,505Vintage 2025 Population Estimates
2020 estimates base?576,962Vintage 2025 Population Estimates
Land area183.8 sq mi2025 Gazetteer Files
Water area6.8 sq mi2025 Gazetteer Files
Total area190.6 sq mi2025 Gazetteer Files
Population density?3,161 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$89,546American Community Survey 2020-2024 5-Year Estimates
Median home value$332,200American Community Survey 2020-2024 5-Year Estimates
Median age39.1American Community Survey 2020-2024 5-Year Estimates
Households216,946American Community Survey 2020-2024 5-Year Estimates
Housing units229,715American 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
+618
6,084 births, 5,466 deaths
Net migration
-1,119
More people moved out than moved in.

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

The 5 areas bordering Delaware 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
Chester CountyPennsylvania31 mi557,116
Philadelphia CountyPennsylvania15 mi1,574,281
Gloucester CountyNew Jersey12 mi312,638
New Castle CountyDelaware9.4 mi588,026
Montgomery CountyPennsylvania8.2 mi877,643

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

Side by side

All 67 counties of Pennsylvania

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

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