County Maps US

Osage County, Kansas

A county in Kansas, ranked 32 of 105 by population.

CountyFIPS 20139

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

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Population
15,693
-54 (-0.3%) since 2020
Land area
705.5
square miles. A further 2.0% of the total area is water
Population density
22.2
people per square mile, computed rather than published
County seat
Lyndon
Seat of county government.
Established
1859
166 years ago
Largest city
Osage City city
Population 2,784.

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 Osage 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 Osage County, Kansas 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 661 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 Osage County ranks

Position among the 105 counties of Kansas, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn KansasNationally
Population15,69332nd of 1052,062nd of 3,144
Land area705.5 sq mi68th of 1051,311th of 3,144
Population density22.2 per sq mi33rd of 1052,158th of 3,144
Median household income$74,46719th of 105876th of 3,143

Full data for Osage County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population15,693Vintage 2025 Population Estimates
Population in 202015,747Vintage 2025 Population Estimates
2020 estimates base?15,770Vintage 2025 Population Estimates
Land area705.5 sq mi2025 Gazetteer Files
Water area14.3 sq mi2025 Gazetteer Files
Total area719.9 sq mi2025 Gazetteer Files
Population density?22.2 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$74,467American Community Survey 2020-2024 5-Year Estimates
Median home value$156,800American Community Survey 2020-2024 5-Year Estimates
Median age42.9American Community Survey 2020-2024 5-Year Estimates
Households6,432American Community Survey 2020-2024 5-Year Estimates
Housing units7,337American 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
-54
158 births, 212 deaths
Net migration
-1
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 6 areas bordering Osage 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
Shawnee CountyKansas24 mi178,607
Coffey CountyKansas24 mi8,467
Franklin CountyKansas21 mi26,299
Lyon CountyKansas21 mi32,266
Douglas CountyKansas9.0 mi120,920
Wabaunsee CountyKansas9.0 mi7,018

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

All 105 counties of Kansas

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

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