Lee County area

Population and density of Lee County

The Census Bureau estimates that 32,914 people lived in Lee County on July 1, 2025. That ranks #1,412 of 3,222 county equivalents nationally and #43 of 102 in Illinois. Since the April 1, 2020 estimates base of 34,152, the population has declined by 1,238 (−3.6%), compared with −0.8% for Illinois as a whole.

With 724.8 square miles of land, that is 45 people per square mile (18 per km²), placing Lee County #1,644 nationally for density and #50 in Illinois. The median county equivalent has 47 people per square mile; the Illinois median is 44. Put another way, there are about 14 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 Lee County

13 incorporated places lie at least partly in Lee County. Together they are home to 20,789 people (63.2%); the other 12,125 (36.8%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Dixon city, with 14,582 residents in the county. By land, Rochelle city is the largest at 13.7 mi² across all its counties.

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

Metropolitan area

Lee County is a central county of the Dixon, IL Micropolitan Statistical Area. Lee County is the area’s only county equivalent, so the micro area has the same 724.8 square miles of land. By combined land it ranks #292 of 542 micropolitan areas, and #417 by population. It belongs to the Dixon-Sterling, IL Combined Statistical Area.

ZIP codes

24 ZIP Code Tabulation Areas have land in Lee County; 14 of them have most of their land inside the county, and the others mainly cover neighboring areas.

605186053060553610066102161031610426105761064610686107161081612436131061318613246133061331613426134961353613676137661378

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 Lee County

Lee County shares a land border with 5 county equivalents. It has more land than 2 of them. The largest neighbor is LaSalle County (1,135.1 mi²) and the smallest is DeKalb County (631.3 mi²). Together with its neighbors, Lee County forms a block of 4,803 mi² of land, of which it holds 15.1%.

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

Lee County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.4 times as much. Illinois’s county land could hold about 77 areas the size of Lee County.

Another way to picture it: the same land area would fill a square about 26.9 miles (43.3 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 Lee County?

Lee County has more land than 1,996 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 Lee County at #1,327 nationally by total area, 101 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 0.5%, compared with a national county-equivalent median of 1.2% — 0.7 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 Lee 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.