Henry County area

Population and density of Henry County

The Census Bureau estimates that 48,095 people lived in Henry County on July 1, 2025. That ranks #1,051 of 3,222 county equivalents nationally and #29 of 102 in Illinois. Since the April 1, 2020 estimates base of 49,284, the population has declined by 1,189 (−2.4%), compared with −0.8% for Illinois as a whole.

With 823.2 square miles of land, that is 58 people per square mile (23 per km²), placing Henry County #1,409 nationally for density and #40 in Illinois. The median county equivalent has 47 people per square mile; the Illinois median is 44. Put another way, there are about 11 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 Henry County

15 incorporated places lie at least partly in Henry County. Together they are home to 33,983 people (70.7%); the other 14,112 (29.3%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Kewanee city, with 12,115 residents in the county. The county seat, Cambridge village, has 2,020 residents.

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

Metropolitan area

Henry County is an outlying county of the Davenport-Moline-Rock Island, IA-IL Metropolitan Statistical Area. Its 4 county equivalents have 380,452 residents on 2,270 square miles of land; Henry County accounts for 36.3% of the land and 12.6% of the residents. By combined land it ranks #143 of 393 metropolitan areas, and #149 by population. It belongs to the Davenport-Moline, IA-IL Combined Statistical Area.

ZIP codes

24 ZIP Code Tabulation Areas have land in Henry County; 16 of them have most of their land inside the county, and the others mainly cover neighboring areas.

612336123461235612386124061241612506125461258612626127361274612776128361344613616141361414614196143461443614656146861490

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 Henry County

Henry County shares a land border with 6 county equivalents. It has more land than 5 of them. The largest neighbor is Bureau County (869.1 mi²) and the smallest is Stark County (288.1 mi²). Together with its neighbors, Henry County forms a block of 4,369.6 mi² of land, of which it holds 18.8%.

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

Henry County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.3 times as much. Illinois’s county land could hold about 67 areas the size of Henry County.

Another way to picture it: the same land area would fill a square about 28.7 miles (46.2 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 Henry County?

Henry County has more land than 2,194 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 Henry County at #1,124 nationally by total area, 96 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 0.3%, compared with a national county-equivalent median of 1.2% — 0.9 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 Henry 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.