Mills County area

Population and density of Mills County

The Census Bureau estimates that 14,793 people lived in Mills County on July 1, 2025. That ranks #2,175 of 3,222 county equivalents nationally and #52 of 99 in Iowa. Since the April 1, 2020 estimates base of 14,500, the population has grown by 293 (+2%), compared with +1.5% for Iowa as a whole.

With 437.4 square miles of land, that is 34 people per square mile (13 per km²), placing Mills County #1,899 nationally for density and #35 in Iowa. The median county equivalent has 47 people per square mile; the Iowa median is 26. Put another way, there are about 19 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 Mills County

8 incorporated places lie at least partly in Mills County. Together they are home to 7,486 people (50.6%); the other 7,307 (49.4%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Glenwood city, with 5,287 residents in the county. Among places with at least 1,000 residents in 2020, Glenwood city grew fastest since then (+3.8%).

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

Metropolitan area

Mills County is an outlying county of the Omaha, NE-IA Metropolitan Statistical Area. Its 8 county equivalents have 1,009,836 residents on 4,345.7 square miles of land; Mills County accounts for 10.1% of the land and 1.5% of the residents. By combined land it ranks #63 of 393 metropolitan areas, and #57 by population. It belongs to the Omaha-Fremont, NE-IA Combined Statistical Area.

ZIP codes

11 ZIP Code Tabulation Areas have land in Mills County; 7 of them have most of their land inside the county, and the others mainly cover neighboring areas.

5150351533515345154051541515515155451561515715164551653

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 Mills County

Mills County shares a land border with 5 county equivalents, including 2 in Nebraska. It has more land than 2 of them. The largest neighbor is Pottawattamie County (951.3 mi²) and the smallest is Sarpy County (238 mi²). Together with its neighbors, Mills County forms a block of 3,118.9 mi² of land, of which it holds 14%.

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

Mills 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. Iowa’s county land could hold about 128 areas the size of Mills County.

Another way to picture it: the same land area would fill a square about 20.9 miles (33.7 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 Mills County?

Mills County has more land than 907 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 Mills County at #2,386 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 0.7%, compared with a national county-equivalent median of 1.2% — 0.4 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 Mills 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.