County Maps US

Delaware County, Ohio

A county in Ohio, ranked 11 of 88 by population.

CountyFIPS 39041

Within Ohio
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 Delaware, the county seat, located via the 2025 Census Gazetteer.

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Population
242,032
+26,851 (+12.5%) since 2020
Land area
443.1
square miles. A further 3.1% of the total area is water
Population density
546
people per square mile, computed rather than published
County seat
Delaware
Seat of county government.
Established
1808
217 years ago
Largest city
Delaware city
Population 46,636.

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, Ohio 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 676 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 88 counties of Ohio, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn OhioNationally
Population242,03211th of 88301st of 3,144
Land area443.1 sq mi43rd of 882,293rd of 3,144
Population density546 per sq mi12th of 88264th of 3,144
Median household income$133,5401st of 8823rd 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
Population242,032Vintage 2025 Population Estimates
Population in 2020215,181Vintage 2025 Population Estimates
2020 estimates base?214,141Vintage 2025 Population Estimates
Land area443.1 sq mi2025 Gazetteer Files
Water area14.2 sq mi2025 Gazetteer Files
Total area457.3 sq mi2025 Gazetteer Files
Population density?546 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$133,540American Community Survey 2020-2024 5-Year Estimates
Median home value$445,500American Community Survey 2020-2024 5-Year Estimates
Median age40.1American Community Survey 2020-2024 5-Year Estimates
Households82,287American Community Survey 2020-2024 5-Year Estimates
Housing units86,269American 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
+527
2,111 births, 1,584 deaths
Net migration
+4,663
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 6 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
Union CountyOhio25 mi73,446
Franklin CountyOhio22 mi1,361,536
Morrow CountyOhio20 mi36,305
Marion CountyOhio12 mi65,115
Licking CountyOhio10 mi185,564
Knox CountyOhio5.0 mi64,002

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

All 88 counties of Ohio

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

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