Calhoun County area

Population and density of Calhoun County

The Census Bureau estimates that 4,300 people lived in Calhoun County on July 1, 2025. That ranks #2,943 of 3,222 county equivalents nationally and #100 of 102 in Illinois. Since the April 1, 2020 estimates base of 4,430, the population has declined by 130 (−2.9%), compared with −0.8% for Illinois as a whole.

With 253.8 square miles of land, that is 17 people per square mile (6.5 per km²), placing Calhoun County #2,413 nationally for density and #98 in Illinois. The median county equivalent has 47 people per square mile; the Illinois median is 44. Put another way, there are about 38 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 Calhoun County

5 incorporated places lie at least partly in Calhoun County. Together they are home to 1,445 people (33.6%); the other 2,855 (66.4%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Hardin village, with 779 residents in the county.

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

Metropolitan area

Calhoun County is an outlying county of the St. Louis, MO-IL Metropolitan Statistical Area. Its 15 county equivalents have 2,814,421 residents on 7,863.5 square miles of land; Calhoun County accounts for 3.2% of the land and 0.2% of the residents. By combined land it ranks #19 of 393 metropolitan areas, and #23 by population. It belongs to the St. Louis-St. Charles-Farmington, MO-IL Combined Statistical Area.

ZIP codes

7 ZIP Code Tabulation Areas have land in Calhoun County; 6 of them have most of their land inside the county, and the others mainly cover neighboring areas.

62006620136203662045620476205362355

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 Calhoun County

Calhoun County shares a land border with 6 county equivalents, including 3 in Missouri. Each of them has more land than Calhoun County. The largest neighbor is Pike County (831.4 mi²) and the smallest is Jersey County (369.6 mi²). Together with its neighbors, Calhoun County forms a block of 3,855.2 mi² of land, of which it holds 6.6%.

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

Calhoun County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 4.1 times as much. Illinois’s county land could hold about 219 areas the size of Calhoun County.

Another way to picture it: the same land area would fill a square about 15.9 miles (25.6 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 Calhoun County?

Calhoun County has more land than 323 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 Calhoun County at #2,881 nationally by total area, 18 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.

Its water share is 10.5%, compared with a national county-equivalent median of 1.2% — 9.3 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 Calhoun 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.