Clark County
Also known as Clark County, Illinois, Clark County, IL
county in Illinois, United States
Key facts
- Country
- United States
- State
- Illinois
- Named after
- George Rogers Clark
- Seat
- Marshall
- Largest city
- Marshall
- Total
- 505 sq mi (1,310 km )
- Land
- 501 sq mi (1,300 km )
- Water
- 3.4 sq mi (8.8 km ) 0.7%
- Estimate 2025
- 15,114
- Density
- 30.8/sq mi (11.9/km )
- Time zone
- UTC−6 ( Central )
- Summer dst
- UTC−5 ( CDT )
- Congressional district
Article
Clark County is a county located in the southeastern part of U.S. state of Illinois, along the Indiana state line. As of the 2020 census, the population was 15,455. Its county seat is Marshall. The county was named for George Rogers Clark, an officer who served in the American Revolution.
History