County Maps US

Washington County, Iowa

A county in Iowa, ranked 27 of 99 by population.

CountyFIPS 19183

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

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Population
22,667
+131 (+0.6%) since 2020
Land area
568.8
square miles. A further 0.4% of the total area is water
Population density
39.8
people per square mile, computed rather than published
County seat
Washington
Seat of county government.
Established
1838
187 years ago
Largest city
Washington city
Population 7,261.

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 Washington 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 Washington County, Iowa 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 795 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 Washington County ranks

Position among the 99 counties of Iowa, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn IowaNationally
Population22,66727th of 991,698th of 3,144
Land area568.8 sq mi54th of 991,793rd of 3,144
Population density39.8 per sq mi27th of 991,679th of 3,144
Median household income$75,64726th of 99801st of 3,143

Full data for Washington County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population22,667Vintage 2025 Population Estimates
Population in 202022,536Vintage 2025 Population Estimates
2020 estimates base?22,561Vintage 2025 Population Estimates
Land area568.8 sq mi2025 Gazetteer Files
Water area2.1 sq mi2025 Gazetteer Files
Total area570.9 sq mi2025 Gazetteer Files
Population density?39.8 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$75,647American Community Survey 2020-2024 5-Year Estimates
Median home value$203,900American Community Survey 2020-2024 5-Year Estimates
Median age40.7American Community Survey 2020-2024 5-Year Estimates
Households8,972American Community Survey 2020-2024 5-Year Estimates
Housing units9,657American 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
+22
299 births, 277 deaths
Net migration
+43
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 Washington 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
Johnson CountyIowa26 mi160,044
Keokuk CountyIowa24 mi9,797
Louisa CountyIowa18 mi10,416
Henry CountyIowa12 mi19,349
Jefferson CountyIowa12 mi15,291
Iowa CountyIowa6.1 mi16,504

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

All 99 counties of Iowa

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

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