County Maps US

Washington County, Missouri

A county in Missouri, ranked 47 of 115 by population.

CountyFIPS 29221

Within Missouri
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 Potosi, the county seat, located via the 2025 Census Gazetteer.

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Population
23,810
+378 (+1.6%) since 2020
Land area
759.9
square miles. A further 0.3% of the total area is water
Population density
31.3
people per square mile, computed rather than published
County seat
Potosi
Seat of county government.
Established
1813
212 years ago
Largest city
Potosi city
Population 2,568.

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, Missouri 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 634 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 115 counties of Missouri, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn MissouriNationally
Population23,81047th of 1151,657th of 3,144
Land area759.9 sq mi17th of 1151,150th of 3,144
Population density31.3 per sq mi56th of 1151,889th of 3,144
Median household income$56,04377th of 1152,403rd 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
Population23,810Vintage 2025 Population Estimates
Population in 202023,432Vintage 2025 Population Estimates
2020 estimates base?23,519Vintage 2025 Population Estimates
Land area759.9 sq mi2025 Gazetteer Files
Water area2.6 sq mi2025 Gazetteer Files
Total area762.5 sq mi2025 Gazetteer Files
Population density?31.3 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$56,043American Community Survey 2020-2024 5-Year Estimates
Median home value$129,400American Community Survey 2020-2024 5-Year Estimates
Median age40.7American Community Survey 2020-2024 5-Year Estimates
Households8,920American Community Survey 2020-2024 5-Year Estimates
Housing units10,734American 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
-98
225 births, 323 deaths
Net migration
+299
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 5 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
Crawford CountyMissouri32 mi22,929
Iron CountyMissouri25 mi9,318
St. Francois CountyMissouri24 mi67,809
Franklin CountyMissouri17 mi108,090
Jefferson CountyMissouri15 mi233,132

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

All 115 counties of Missouri

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

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