• county
  • FIPS 17103
  • Largest town: Dixon

Lee County, Illinois

Lee County had 33,544 residents in the Census Vintage 2024 estimate, on 724.8 square miles of land. It ranks 42nd of 102 in Illinois by population and 19th by land area.

Population
33,544
#42 of 102 in Illinois · #1,350 in US
Area
724.8 sq mi
#19 of 102 in Illinois · #1,226 in US
Density
46 / sq mi
#49 of 102 in Illinois · #1,543 in US
Median household income
$66,598
#49 of 102 in Illinois · #1,243 in US

Census Vintage 2024 estimates · SAIPE 2023 income · 2024 Gazetteer land area

Lee County within Illinois. Pin: Springfield.

Measure from here

Tools and pages that start from Lee County

Lee County population, land area and income

Lee County had 33,544 residents in the Census Vintage 2024 estimate, on 724.8 square miles of land. It ranks 42nd of 102 in Illinois by population and 19th by land area. That works out to 46.3 people per square mile, below the US average of 96.3, and above the national county median.

The median county-equivalent in Illinois has 24,447 residents; Lee County is somewhat larger.

Its SAIPE 2023 median household income of $66,598 is above the national county median among 3,143 counties with an estimate.

National rank among 3,144

Population

33,544

3144th1st

1350th of 3,144 (US)

Land area

725 sq mi

3144th1st

1226th of 3,144 (US)

Density

46.3 / sq mi

3144th1st

1543rd of 3,144 (US)

Median household income

$66,598

3143rd1st

1243rd of 3,143 (US)

Rank within Illinois (102)

Population

33,544

102nd1st

42nd of 102 (IL)

Land area

725 sq mi

102nd1st

19th of 102 (IL)

Density

46.3 / sq mi

102nd1st

49th of 102 (IL)

Median household income

$66,598

102nd1st

49th of 102 (IL)

How Lee County's population changed since 2020

Lee County lost 519 residents between the July 2020 and July 2024 estimates, a drop of 1.5%. That ranks 46th of 102 in Illinois for growth. The median Illinois county changed by -1.7%, and the state as a whole by -0.7%.

Since the April 2020 estimates base, Lee County recorded 1,275 births and 1,790 deaths, a natural change of -515. Net international migration added +158 and net domestic migration, people moving to or from other US counties, came to -244. The largest single component was natural change, which removed 515 people.

34.1k202034.2k202133.9k202233.6k202333.5k2024
Census Vintage 2024 county estimates for July 1 of each year. The axis starts above zero so year-to-year changes are visible.

Components of change, April 2020 to July 2024

Births
1,275
Deaths
1,790
Net international migration
+158
Net domestic migration
-244
Change, July 2023 to July 2024
-62

Where Lee County is

The Census internal point of Lee County is at 41.747400, -89.299400. It sits in UTM zone 16N. The map shades Illinois's 102 county-equivalents by population change from 2020 to 2024, darker for faster growth, with Lee County outlined. Dots are towns of 1,000+ people with residents in it.

Piatt County: -0.3%Hamilton County: -2.2%Williamson County: -0.1%Edgar County: -2.4%Macoupin County: -2.3%Marshall County: -1.3%Putnam County: +0.0%Richland County: -2.8%Washington County: -1.4%Lee County: -1.5%Douglas County: +0.2%Cook County: -1.6%Effingham County: -0.3%Edwards County: -3.6%Cass County: -2.0%Clay County: -3.4%Knox County: -2.2%LaSalle County: -0.9%Cumberland County: -1.3%Warren County: -3.7%Moultrie County: -0.9%Menard County: -2.5%Fayette County: -1.5%Boone County: -0.0%Lawrence County: -3.2%Marion County: -3.2%Champaign County: +3.0%Clark County: -2.4%Ford County: -0.4%Wayne County: -1.4%Logan County: -1.4%Grundy County: +2.5%Jasper County: -1.8%Crawford County: -1.3%McDonough County: -1.7%Clinton County: +0.5%Perry County: -3.0%Montgomery County: -2.2%Henry County: -2.0%Livingston County: -1.2%Scott County: -3.8%Alexander County: -11.2%Bureau County: -2.2%Brown County: +1.1%Mason County: -3.9%Calhoun County: -4.1%Greene County: -4.3%Coles County: -1.4%Kendall County: +8.2%Lake County: +0.7%Mercer County: -2.2%St. Clair County: -2.3%Wabash County: -3.0%Bond County: -1.7%DuPage County: +0.6%Gallatin County: -5.2%Stephenson County: -3.3%McHenry County: +1.9%White County: -3.0%Saline County: -3.9%Christian County: -2.2%Sangamon County: -1.0%Massac County: -3.6%Macon County: -2.9%Johnson County: -0.0%Jo Daviess County: -2.6%Peoria County: -1.0%DeKalb County: +1.0%Pope County: -1.5%De Witt County: -0.9%Schuyler County: -1.7%Fulton County: -3.1%Ogle County: -0.8%Jersey County: -1.6%Iroquois County: -3.3%Kankakee County: -0.9%Rock Island County: -1.1%Pulaski County: -5.8%Kane County: +0.9%Union County: -2.4%Whiteside County: -1.7%Woodford County: -0.3%Carroll County: -1.5%Adams County: -2.3%Hardin County: -2.6%Madison County: -1.0%Hancock County: -3.1%Monroe County: +0.0%Tazewell County: -1.1%Jackson County: -0.1%Vermilion County: -3.9%Randolph County: -0.6%McLean County: +0.5%Morgan County: -2.6%Shelby County: -1.7%Will County: +1.7%Winnebago County: -0.4%Jefferson County: -2.4%Stark County: -2.2%Henderson County: -4.5%Pike County: -2.6%Franklin County: -1.8%
Change 2020 to 2024
  1. < -3.0%
  2. < -2.2%
  3. < -1.4%
  4. < -0.3%
  5. ≥ -0.3%
no data

Orange pin: Lee County internal point. Dark pin: Springfield.

Internal point

Decimal
41.747400, -89.299400
DMS
41°44'50.64"N 89°17'57.84"W
UTM
16N 308812.0E 4624286.1N
Geohash
dp2mrzyhj
Plus code
86HGPPW2+X6

Towns in Lee County

2 incorporated places of 1,000+ people have residents in Lee County, 17,380 people together, or 52% of the county. Each figure counts only the part of the town inside Lee County; towns marked "part" extend into another county. The largest is Dixon with 15,156.

  1. 01Dixon15,156
  2. 02Amboy2,224
Census Vintage 2024 subcounty estimates, county parts of incorporated places (SUMLEV 157).

Counties bordering Lee County

The Census 2024 county adjacency file lists 5 neighbors for Lee County. The most populous is LaSalle County, IL, with 108,390 residents. Distances run between Census internal points in a straight line.

Distance to Springfield and the nearest big city

Springfield is 137.1 miles S of Lee County's internal point in a straight line. The nearest place of 100,000 or more is Rockford, IL (population 147,486), 37.4 miles away. The nearest place of 10,000 or more is Dixon, IL (population 15,156), 11.3 miles away.

Lee County FIPS code

The FIPS code of Lee County is 17103: state code 17 for Illinois plus county code 103. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $66,598.

Questions people ask

What is the population of Lee County, Illinois?

The Census Vintage 2024 estimate for July 1, 2024 is 33,544. That is down 519 people (1.5%) from the July 2020 estimate of 34,063.

What is the FIPS code of Lee County?

17103. The first two digits (17) are Illinois; the last three (103) identify the county.

What is the largest town in Lee County?

Dixon, with 15,156 residents inside Lee County in 2024.

Which counties border Lee County?

5 county-equivalents border it in the Census 2024 adjacency file: LaSalle County, IL; DeKalb County, IL; Whiteside County, IL; Ogle County, IL; Bureau County, IL.

Sources and data as of

Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.

  1. 01Census Vintage 2024 county population estimates
  2. 02Census 2024 Gazetteer, counties
  3. 03Census SAIPE 2023 state and county estimates
  4. 04Census Vintage 2024 subcounty population estimates
  5. 05Census 2024 county adjacency file
  6. 06Census 2024 cartographic boundary file, counties (1:5,000,000)

How every number is computed: methodology. Spotted a wrong figure? Report an error.