Clark County GIS Maps
Clark County, Illinois, has 15,455 residents and covers 501.4 square miles. The population declined 5.4% between the 2010 and 2020 census. More residents left than arrived over that decade. The FIPS code for Clark County is 17023.
Marshall is the county's largest population center. Clark County also includes 7 zip codes, 4 public school districts and 32 municipalities. Those boundaries help explain why population, schools, and housing can look different from one part of the county to another. The map below shows how those county lines, zip codes, and school districts fit together, and the sections that follow use that same geography to show population, demographics, school enrollment and housing patterns in more detail.
Maps, GIS layers and sample data. Paid packages add full layers, analytics and database files.
Clark County Trends
- Population
- 15,455▾
- Median Home Value
- $123,100▴
- K-12 Enrollment
- 2,723▾
County analytics dashboards with historical trends & projections included in package downloads.
Free starter access previews county maps, lightweight GIS, and sample data. Paid packages unlock full GIS layers, analytics, and database files.
Clark County Maps
The maps below show a few of the county map styles included in our downloads. County packages include map exports in JPEG, PNG, SVG, PDF and GeoTIFF formats plus more than 20 GIS layers for mapping, research and analysis. Available layers include zip codes, area codes, subdivisions, school districts, political boundaries, roads, water features, points of interest and more.
County packages also include historical county demographics, business intelligence, analytical dashboards, AI-ready prompts, markdown files and related reference data. Everything is organized to save hours of manual work collecting current data, cleaning it and joining it together. That makes it easier to move faster on analytics, due diligence, business planning and location research. Paid packages are built for commercial use, but some package contents include source-specific attribution or notice guidance. Review Licensing & Data Source Notices.
Clark County Population
Clark County had 15,455 residents in 2020. That was 5.4% lower than in 2010. Clark County had 1,553 fewer people in 2020 than it did in 2000, which points to a long-term population decline. The county is fairly spread out, with about 31 people per square mile. Some of the county's most populated postal areas include Marshall, Casey and Martinsville.
Population Trend in Clark County IL
Clark County Population per 2000, 2010 and 2020 census counts with a baseline 2030 projection.
Clark County Zip Codes
Clark County has 7 zip codes. Some of the county's most populated zip codes include Marshall (62441), Casey (62420) and Martinsville (62442). Marshall is the largest zip by population, with about 7,236 residents or 47% of the county total. Together, the three largest zips account for about 89% of all county residents based on 2020 population estimates.
Most Populated Zip Codes in Clark County IL
| ZIP | Area | Population | Trend |
|---|---|---|---|
| 62441 | Marshall | 7,236 | ▾ -2.2% |
| 62420 | Casey | 4,196 | ▾ -11.8% |
| 62442 | Martinsville | 2,322 | ▾ -4.1% |
| 62477 | West Union | 904 | ▾ -4.4% |
| 62474 | Westfield | 749 | ▾ -11.7% |
| Download all zip code data | |||
Clark County Zip Code populations and trends per most recent census data.
Clark County Demographics
Clark County has a median age of 42, which makes the county a little older than Illinois overall. About 22.3% of residents are under 18, while 19.7% are 65 or older. That gives the county a fairly even mix of younger families and older adults. The largest age group is 25 to 44 at about 29.5% of the population, which points to a solid working-age base. About 24.3% of adults have a bachelor's degree or higher, above the statewide figure of 37.2%. The county is mostly White by population, though Hispanic, Asian, Black and multiracial residents are also part of the local mix.
Key Demographics for Clark County IL
Median Age
42
Under 18
22.3%
Age 65+
19.7%
Bachelor's+
24.3%
Clark County School Districts
Clark County is served by 4 public school districts with 2,723 students enrolled in 2024. The largest districts on the county map are Marshall Community Unit 2C, Casey-Westfield Community Unit 4C and Martinsville Community Unit 3C. Those three districts account for about 90% of public school enrollment in the map area. Total enrollment has stayed fairly steady in recent years, but it is slightly lower than it was in 2017.
Largest School Districts by Enrollment in Clark County IL
| District | Enrollment | Share | Trend |
|---|---|---|---|
| Marshall Community Unit School District 2C | 1,181 | 43.4% | ▾ -1.3% |
| Casey-Westfield Community Unit School District 4C | 891 | 32.7% | ▾ -0.4% |
| Martinsville Community Unit School District 3C | 384 | 14.1% | ▴ 2.9% |
| Hutsonville Community Unit School District 1 | 267 | 9.8% | ▾ -9.2% |
| Download all school district data | |||
Clark County school district enrollment and trends per most recent NCES reporting data.
Clark County Housing & Real Estate
Clark County has a median home value of $123,100 and a median gross rent of $828. About 82% of occupied homes in the county are owner-occupied, so the local housing market leans heavily toward ownership. Home values run below the Illinois median, while rents come in below the state average. In March 2026, the median listing price was $181,675 and homes spent about 57 days on the market.
Clark County Housing Mix
Clark County housing mix: owner, renter and vacant units.
Clark County Housing Trends
Clark County median home value and rent trend (last 5 years).
Businesses in Clark County, IL
Clark County has 748 business listings across 272 categories. The largest categories in Clark County business listings are Churches & Religious Organizations (40, 5.3%), Auto Repair (16, 2.1%), and Insurance Agencies (13, 1.7%). The full Clark County business listings dataset includes names, categories, addresses and contact details where available. Clark County packages also include U.S. Census County Business Patterns data with establishment counts, employment and payroll by industry sector.
Top Business Categories in Clark County, IL
| Category | Businesses | Share |
|---|---|---|
| Churches & Religious Organizations | 40 | 5.3% |
| Auto Repair | 16 | 2.1% |
| Insurance Agencies | 13 | 1.7% |
| Fast Food | 12 | 1.6% |
| Pizza Restaurants | 12 | 1.6% |
| Convenience Stores | 11 | 1.5% |
| Banks & Credit Unions | 11 | 1.5% |
| Farm | 11 | 1.5% |
| Gas Stations | 10 | 1.3% |
| Hotels | 10 | 1.3% |
Clark County Business Listings
| Business | Category | City |
|---|---|---|
| Lucas Eitel Accounting | Accountant | Marshall |
| Birkeys Farm Store | Agricultural Service | Casey |
| Littlejohn Grain | Agriculture | West Union |
| Casey Municipal Airport | Airport | Casey |
| Thrive Dispensary Casey | Alcohol And Drug Treatment Center | Casey |
| Ambulance Service Marshall | Ambulance And Ems Services | Marshall |
| Reflections Family Restaurant | American Restaurants | Casey |
| Deborahs Attic | Antique Store | Casey |
| Stewart's Appliance Repair | Appliance Store | Marshall |
| Auctions & Appraisals of Illiana | Appraisal Services | Marshall |
| Download Clark County business listings | ||
Clark County business listings sourced from Overture Maps. Includes locations with a high level of confidence.
Clark County Basemaps
Clark County map and data packages include a set of useful basemaps to help you get started quickly. These include a custom light grey canvas, USGS topo, imagery and other reference layers that make it easier to build clear, meaningful county maps using the included GIS layers, your own data or both. Pre-rendered map tiles for the light grey basemap are included so you can use them offline or host them on your own CDN.
Get the Full Clark County Data Package
This page shows a preview of what's included in the Clark County data package. The full package gives you a ready-to-use county data system with GIS layers, historical data, maps, database files and planning tools that save hours of manual data gathering, cleanup and joins. Everything is organized to help you skip data wrangling and start analysis faster.
- 20+ GIS layers for zip codes, school districts, roads, water, boundaries and more
- Historical county demographics, housing, income and trend data
- ZIP code population files and school district enrollment history
- Database files, markdowns, AI-ready prompts and documentation
- Map exports in PNG, JPEG, PDF, SVG and GeoTIFF formats
- Offline-ready data explorer, map and analytics tools
Paid packages support commercial use, client work, and derived outputs. Some package contents may include source-specific attribution or provider notices. See Licensing & Data Source Notices.
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Nearby Counties
Browse county data pages for the counties that border Clark County. These nearby pages include the same mix of county maps, demographic summaries, school district context, housing trends and package links.