Cerro Gordo County area

Population and density of Cerro Gordo County

The Census Bureau estimates that 42,372 people lived in Cerro Gordo County on July 1, 2025. That ranks #1,163 of 3,222 county equivalents nationally and #13 of 99 in Iowa. Since the April 1, 2020 estimates base of 43,123, the population has declined by 751 (−1.7%), compared with +1.5% for Iowa as a whole.

With 568.3 square miles of land, that is 75 people per square mile (29 per km²), placing Cerro Gordo County #1,213 nationally for density and #15 in Iowa. The median county equivalent has 47 people per square mile; the Iowa median is 26. Put another way, there are about 8.6 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 Cerro Gordo County

11 incorporated places lie at least partly in Cerro Gordo County. Together they are home to 37,502 people (88.5%); the other 4,870 (11.5%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Mason City city, with 26,853 residents in the county.

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

Metropolitan area

Cerro Gordo County is a central county of the Mason City, IA Micropolitan Statistical Area. Its 2 county equivalents have 49,710 residents on 968.4 square miles of land; Cerro Gordo County accounts for 58.7% of the land and 85.2% of the residents. By combined land it ranks #190 of 542 micropolitan areas, and #228 by population.

ZIP codes

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

5040150428504335043450444504495045650457504585046450467504685046950475504775047950482

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 Cerro Gordo County

Cerro Gordo County shares a land border with 5 county equivalents. It has more land than 3 of them. The largest neighbor is Franklin County (582 mi²) and the smallest is Worth County (400.1 mi²). Together with its neighbors, Cerro Gordo County forms a block of 3,091.2 mi² of land, of which it holds 18.4%.

How big is Cerro Gordo County compared with U.S. states?

Cerro Gordo County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.8 times as much. Iowa’s county land could hold about 98 areas the size of Cerro Gordo County.

Another way to picture it: the same land area would fill a square about 23.8 miles (38.4 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 Cerro Gordo County?

Cerro Gordo County has more land than 1,426 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 Cerro Gordo County at #1,877 nationally by total area, 81 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 1.2%, compared with a national county-equivalent median of 1.2%. The two percentages are within 0.1 percentage points of each other. 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 Cerro Gordo 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.