Atchison County area

Population and density of Atchison County

The Census Bureau estimates that 16,172 people lived in Atchison County on July 1, 2025. That ranks #2,094 of 3,222 county equivalents nationally and #31 of 105 in Kansas. Since the April 1, 2020 estimates base of 16,345, the population has declined by 173 (−1.1%), compared with +1.3% for Kansas as a whole.

With 431.2 square miles of land, that is 38 people per square mile (14 per km²), placing Atchison County #1,812 nationally for density and #18 in Kansas. The median county equivalent has 47 people per square mile; the Kansas median is 8.1. Put another way, there are about 17 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 Atchison County

5 incorporated places lie at least partly in Atchison County. Together they are home to 11,738 people (72.6%); the other 4,434 (27.4%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Atchison city, with 10,789 residents in the county.

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

Metropolitan area

Atchison County is a central county of the Atchison, KS Micropolitan Statistical Area. Atchison County is the area’s only county equivalent, so the micro area has the same 431.2 square miles of land. By combined land it ranks #463 of 542 micropolitan areas, and #534 by population. It belongs to the Kansas City-Overland Park-Kansas City, MO-KS Combined Statistical Area.

ZIP codes

10 ZIP Code Tabulation Areas have land in Atchison County; 5 of them have most of their land inside the county, and the others mainly cover neighboring areas.

66002660166602366041660586606066088664246643666439

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 Atchison County

Atchison County shares a land border with 7 county equivalents, including 2 in Missouri. It has more land than 3 of them. The largest neighbor is Jackson County (656.2 mi²) and the smallest is Doniphan County (393.5 mi²). Together with its neighbors, Atchison County forms a block of 3,875.9 mi² of land, of which it holds 11.1%.

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

Atchison County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.4 times as much. Kansas’s county land could hold about 190 areas the size of Atchison County.

Another way to picture it: the same land area would fill a square about 20.8 miles (33.4 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 Atchison County?

Atchison County has more land than 867 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 Atchison County at #2,426 nationally by total area, 71 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 0.6%, compared with a national county-equivalent median of 1.2% — 0.6 percentage points lower. 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 Atchison 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.