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Clark County, IL
5 cities and towns and 7 ZIP codes in Clark County, Illinois.
Population
15,266
Land area
501sq mi
People per sq mi
30
ZIP codes
7
Cities and towns in Clark County
Clark County at a glance
- Clark County is 87% less dense than Illinois as a whole.
- Households here earn a median of $72,927 a year, 13% less than the Illinois figure of $83,390.
- A typical owner-occupied home is valued at $132,400 (50% below Illinois) and median rent is $861 a month.
- The biggest population centers are Marshall (4,040), Casey (2,239) and Martinsville (1,187).
Local data for Clark County, IL
Counts from official public data
Housing and community stats
Clark County, IL, American Community Survey 2020-2024
Median household income
$72,927
Poverty rate
9.1%
Median home value
$132,400
Prices +3.1% in a year
Median rent
$861/mo
Homeownership
80.3%
Bachelor's or higher
24.9%
Median age
42.6
Average commute
25.2 min
Largest reported origins and ancestries: German Americans (3,420), Irish Americans (2,010), Polish Americans (309).
Economy and federal money
Jobs, income, federal spending and pandemic loans
Unemployment rate
3.9%
Sep 2026, -1.0 pts in a year
Average annual pay
$46,794
4,304 jobs, 2025
Income per person
$55,544
BEA, 2024
Federal spending
$115M
FY 2026, $7,451 per person
PPP loans
$30.4M
806 loans, 3,158 jobs reported
Campaign donations
$71.8K
Itemized, 2026 cycle
How people get to work
Clark County, IL, workers 16 and older. American Community Survey 5-year estimates
- Drove alone84.1%
- Carpooled8.3%
- Public transit0.0%
- Walked1.5%
- Bicycle0.0%
- Taxi, ride-hailing, motorcycle or other0.9%
- Worked from home5.2%
Average one-way commute: 25.2 minutes for people who do not work from home.
Environment and hazard risk
Clark County, IL, from FEMA, NOAA and EPA
Natural hazard risk
Very Low
Top: earthquake
Storm events since 1996
270
Most often thunderstorm wind
Flood insurance policies
6
0.1% of homes, county
July high / Jan low
88° / 19°F
45.5 inches of rain a year
Hazards, floods and storm historyCheck a flood zone8 historic places
Health statistics
Share of adults in Clark County, IL, CDC PLACES estimates
Obesity
37.3%
U.S. 33.3% +4.0 pts
Diabetes
12.0%
U.S. 12.1% about the same
Smoking
14.9%
U.S. 12.8% +2.1 pts
Uninsured (18-64)
7.3%
U.S. 11.1% -3.8 pts
Cities, towns and ZIP codes in Clark County
Population shown
Frequently asked questions
- What is the largest city in Clark County, IL?
- Marshall is the largest city or town in Clark County, with about 4,040 residents.
- How many ZIP codes are in Clark County?
- Clark County includes 7 ZIP Code Tabulation Areas, including 62420, 62423, 62441, 62442, 62474.
- What is the population of Clark County, IL?
- About 15,266 people live in Clark County, based on American Community Survey 5-year estimates.
- What counties border Clark County?
- Clark County borders Vigo County, IN, Coles County, Sullivan County, IN, Crawford County, Edgar County, Cumberland County, Jasper County.
Source: U.S. Census Bureau (TIGER/Line boundaries, American Community Survey) · Data as of 12/31/2023