County Maps US

Marion County, Kansas

A county in Kansas, ranked 37 of 105 by population.

CountyFIPS 20115

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

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Population
11,634
-154 (-1.3%) since 2020
Land area
944.3
square miles. A further 1.0% of the total area is water
Population density
12.3
people per square mile, computed rather than published
County seat
Marion
Seat of county government.
Established
1855
170 years ago
Largest city
Hillsboro city
Population 2,646.

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 Marion 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 Marion 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 676 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 Marion 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
Population11,63437th of 1052,309th of 3,144
Land area944.3 sq mi20th of 105753rd of 3,144
Population density12.3 per sq mi47th of 1052,489th of 3,144
Median household income$64,69549th of 1051,654th of 3,143

Full data for Marion County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population11,634Vintage 2025 Population Estimates
Population in 202011,788Vintage 2025 Population Estimates
2020 estimates base?11,829Vintage 2025 Population Estimates
Land area944.3 sq mi2025 Gazetteer Files
Water area9.4 sq mi2025 Gazetteer Files
Total area953.7 sq mi2025 Gazetteer Files
Population density?12.3 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$64,695American Community Survey 2020-2024 5-Year Estimates
Median home value$124,200American Community Survey 2020-2024 5-Year Estimates
Median age43.5American Community Survey 2020-2024 5-Year Estimates
Households4,750American Community Survey 2020-2024 5-Year Estimates
Housing units5,693American 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
130 births, 152 deaths
Net migration
-22
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 7 areas bordering Marion 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
Chase CountyKansas31 mi2,572
McPherson CountyKansas30 mi30,064
Dickinson CountyKansas24 mi18,637
Harvey CountyKansas18 mi33,580
Butler CountyKansas17 mi69,484
Morris CountyKansas12 mi5,348
Saline CountyKansasa single point53,377

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.