Osage County area

Population and density of Osage County

The Census Bureau estimates that 15,693 people lived in Osage County on July 1, 2025. That ranks #2,127 of 3,222 county equivalents nationally and #32 of 105 in Kansas. Since the April 1, 2020 estimates base of 15,770, the population has declined by 77 (−0.5%), compared with +1.3% for Kansas as a whole.

With 705.5 square miles of land, that is 22 people per square mile (8.6 per km²), placing Osage County #2,237 nationally for density and #33 in Kansas. The median county equivalent has 47 people per square mile; the Kansas median is 8.1. Put another way, there are about 29 acres of land per resident.

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Osage County

9 incorporated places lie at least partly in Osage County. Together they are home to 8,360 people (53.3%); the other 7,333 (46.7%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Osage City city, with 2,784 residents in the county. The county seat, Lyndon city, has 1,032 residents.

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Osage County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Osage County is an outlying county of the Topeka, KS Metropolitan Statistical Area. Its 5 county equivalents have 233,052 residents on 3,232.7 square miles of land; Osage County accounts for 21.8% of the land and 6.7% of the residents. By combined land it ranks #94 of 393 metropolitan areas, and #209 by population.

ZIP codes

15 ZIP Code Tabulation Areas have land in Osage County; 9 of them have most of their land inside the county, and the others mainly cover neighboring areas.

664026640966413664146645166510665236652466528665376654366546668566686866871

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Osage County

Osage County shares a land border with 6 county equivalents. It has more land than 4 of them. The largest neighbor is Lyon County (847.5 mi²) and the smallest is Douglas County (455.8 mi²). Together with its neighbors, Osage County forms a block of 4,545.8 mi² of land, of which it holds 15.5%.

How big is Osage County compared with U.S. states?

Osage County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.5 times as much. Kansas’s county land could hold about 116 areas the size of Osage County.

Another way to picture it: the same land area would fill a square about 26.6 miles (42.7 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Osage County?

Osage County has more land than 1,911 of the other 3,221 county equivalents in the dataset.

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Osage County at #1,365 nationally by total area, 54 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 2%, compared with a national county-equivalent median of 1.2% — 0.8 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Osage County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.