Peoria County area

Population and density of Peoria County

The Census Bureau estimates that 178,553 people lived in Peoria County on July 1, 2025. That ranks #393 of 3,222 county equivalents nationally and #12 of 102 in Illinois. Since the April 1, 2020 estimates base of 182,008, the population has declined by 3,455 (−1.9%), compared with −0.8% for Illinois as a whole.

With 618.7 square miles of land, that is 289 people per square mile (111 per km²), placing Peoria County #522 nationally for density and #12 in Illinois. The median county equivalent has 47 people per square mile; the Illinois median is 44. Put another way, there are about 2.2 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 Peoria County

17 incorporated places lie at least partly in Peoria County. Together they are home to 143,715 people (80.5%); the other 34,838 (19.5%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Peoria city, with 110,920 residents in the county. Among places with at least 1,000 residents in 2020, Bellevue village grew fastest since then (+0.5%).

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

Metropolitan area

Peoria County is a central county of the Peoria, IL Metropolitan Statistical Area. Its 5 county equivalents have 363,505 residents on 2,467.7 square miles of land; Peoria County accounts for 25.1% of the land and 49.1% of the residents. By combined land it ranks #134 of 393 metropolitan areas, and #157 by population. It belongs to the Peoria-Canton, IL Combined Statistical Area.

ZIP codes

28 ZIP Code Tabulation Areas have land in Peoria County; 25 of them have most of their land inside the county, and the others mainly cover neighboring areas.

61451614896151761523615256152661528615296153161533615366153961547615526155961562615656156961602616036160461605616066160761614616156161661625

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 Peoria County

Peoria County shares a land border with 6 county equivalents. It has more land than 3 of them. The largest neighbor is Fulton County (865.7 mi²) and the smallest is Stark County (288.1 mi²). Together with its neighbors, Peoria County forms a block of 4,049.7 mi² of land, of which it holds 15.3%.

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

Peoria County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.7 times as much. Illinois’s county land could hold about 90 areas the size of Peoria County.

Another way to picture it: the same land area would fill a square about 24.9 miles (40 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 Peoria County?

Peoria County has more land than 1,666 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 Peoria County at #1,641 nationally by total area, 85 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 1.8%, compared with a national county-equivalent median of 1.2% — 0.7 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 Peoria 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.