County Maps US

Warren County, Ohio

A county in Ohio, ranked 10 of 88 by population.

CountyFIPS 39165

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

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Population
257,181
+13,970 (+5.7%) since 2020
Land area
401.4
square miles. A further 1.5% of the total area is water
Population density
641
people per square mile, computed rather than published
County seat
Lebanon
Seat of county government.
Established
1803
222 years ago
Largest city
Mason city
Population 35,834.

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 Warren 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 Warren 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 726 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 Warren 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
Population257,18110th of 88287th of 3,144
Land area401.4 sq mi79th of 882,519th of 3,144
Population density641 per sq mi11th of 88224th of 3,144
Median household income$110,1323rd of 8896th of 3,143

Full data for Warren County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population257,181Vintage 2025 Population Estimates
Population in 2020243,211Vintage 2025 Population Estimates
2020 estimates base?242,345Vintage 2025 Population Estimates
Land area401.4 sq mi2025 Gazetteer Files
Water area6.1 sq mi2025 Gazetteer Files
Total area407.5 sq mi2025 Gazetteer Files
Population density?641 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$110,132American Community Survey 2020-2024 5-Year Estimates
Median home value$349,400American Community Survey 2020-2024 5-Year Estimates
Median age40.1American Community Survey 2020-2024 5-Year Estimates
Households92,052American Community Survey 2020-2024 5-Year Estimates
Housing units96,061American 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
+281
2,427 births, 2,146 deaths
Net migration
+1,853
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 Warren 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
Butler CountyOhio23 mi400,128
Clinton CountyOhio22 mi42,301
Clermont CountyOhio14 mi216,977
Montgomery CountyOhio13 mi539,598
Greene CountyOhio7.4 mi174,322
Hamilton CountyOhio6.5 mi838,418

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.