County Maps US

Riley County, Kansas

A county in Kansas, ranked 7 of 105 by population.

CountyFIPS 20161

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

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Population
72,598
+587 (+0.8%) since 2020
Land area
609.7
square miles. A further 2.0% of the total area is water
Population density
119
people per square mile, computed rather than published
County seat
Manhattan
Seat of county government.
Established
1855
170 years ago
Largest city
Manhattan city
Population 54,672 for the whole place, which extends beyond this county.

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 Riley 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 Riley 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 691 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 Riley 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
Population72,5987th of 105769th of 3,144
Land area609.7 sq mi82nd of 1051,588th of 3,144
Population density119 per sq mi7th of 105799th of 3,144
Median household income$61,09870th of 1051,981st of 3,143

Full data for Riley County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population72,598Vintage 2025 Population Estimates
Population in 202072,011Vintage 2025 Population Estimates
2020 estimates base?71,962Vintage 2025 Population Estimates
Land area609.7 sq mi2025 Gazetteer Files
Water area12.4 sq mi2025 Gazetteer Files
Total area622.1 sq mi2025 Gazetteer Files
Population density?119 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$61,098American Community Survey 2020-2024 5-Year Estimates
Median home value$237,100American Community Survey 2020-2024 5-Year Estimates
Median age25.5American Community Survey 2020-2024 5-Year Estimates
Households27,695American Community Survey 2020-2024 5-Year Estimates
Housing units30,755American 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
+300
739 births, 439 deaths
Net migration
+219
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 Riley 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
Pottawatomie CountyKansas65 mi27,186
Geary CountyKansas39 mi36,338
Clay CountyKansas24 mi7,990
Wabaunsee CountyKansas15 mi7,018
Marshall CountyKansas12 mi9,852
Washington CountyKansas8.1 mi5,533

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.