ZIP Codes of Lee County, IL

Population & People
Population & People
Total Population
34,166
Household Income
Household Income
Median Income
$76,604
Housing
Housing
Total Housing Units
15,242
Business & Economy
Business & Economy
Total Businesses
693
Employment
Employment
Employment Rate
52.77%
Education
Education
Bachelor's Degree+
20.02%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 14 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:14 ZIP Codes (11 Standard, 3 PO Box, 0 Unique) [See All]
Area Codes:779 / 815
Timezone:Central (GMT -06:00)
Local Time:2:12:01 PM
Population:34,166 [See All]
FIPS:17103
CBSA:Dixon, IL
Land Area:699 sq mi
Water Area:4 sq mi
Coordinates:41.7598, -89.2483
Quick Link:
https://www.zip-codes.com/county/il-lee.asp
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Illinois's #40 most populous county
34,166 residents across 14 ZIPs — #40 of 102 Illinois counties.

Standout ZIPs in this County


Most Populous
Dixon · 22,308 people
65.3% of county total
Highest Income
Steward · $109,375 median
1.4× county average
Largest Land Area
Dixon · 155.0 sq mi
Spans the most ground
Fastest Growth
Dixon · -2.7% (10-yr)
22,928 → 22,308 residents
Most Educated
Franklin Grove · 28.2% bachelor's+
324 of 1,150 adults 25+

Things worth knowing about Lee County


34,166 residents live across 14 ZIPs covering 699 sq mi, served by 14 distinct USPS-recognized cities.

Population moved from 35,710 to 34,166 from 2014 to 2024 — a -4.3% change. 3 ZIPs gained residents, 10 lost (and 1 held flat).

The county's wealthiest ZIP 60553 (Steward, $109,375 median) and poorest ZIP 61367 (Sublette, $60,824) are 17.2 miles apart — a 1.8× income gap across local geography.

Median home values vary 2.7× across this county — from $97,200 in 61318 (Compton) to $264,500 in 60530 (Lee).

Density varies 23× across the county — from 6 people/sq mi in 61042 (Harmon) to 144 in 61021 (Dixon).

Educational attainment ranges from 8.9% bachelor's+ in 61318 (Compton) to 30.6% in 60553 (Steward) — the breadth of educational profiles across the area.

Within Illinois, this is the #40 most populous of 102 counties and ranks #36 for median household income .

Weighted by population, the typical household earns about $71,280 across the county — reflecting what a typical resident sees, not a simple ZIP average.

20.0% of adults age 25+ hold a bachelor's degree or higher (5,041 of 25,174 reporting).

11 Standard delivery, 3 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Lee County


Big & sparse

A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.

Total area
699
square miles
Avg density
48.9
people per sq mi
Population
34,166
across 14 ZIPs
Dixon
155.0 sq mi
22,308 residents
Amboy
117.0 sq mi
3,347 residents
Ashton
69.5 sq mi
1,541 residents

Single-ZIP anchor

One ZIP holds the majority of this county's population — a sign of a county built around a single city or town.

Dixon

All ZIP Codes in Lee County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
61021DixonStandard22,308$69,127155.0-2.7%
61310AmboyStandard3,347$69,756117.0-14.0%
61006AshtonStandard1,541$75,93869.5-8.8%
61031Franklin GroveStandard1,492$75,44643.8-9.0%
61353Paw PawStandard1,282$66,71934.8-3.0%
60530LeeStandard992$96,25029.778.4%
61367SubletteStandard843$60,82447.810.8%
60553StewardStandard722$109,37549.4-16.4%
61318ComptonStandard595$63,02133.4-30.0%
61378West BrooklynStandard513$85,35055.4-5.0%
61042HarmonStandard404$70,83363.3-12.4%
61324EldenaPO Box970.370.2%
61057NachusaPO Box300.0-80.0%
61331Lee CenterPO Box00.0

Adjacent & Nearby Counties