Clark County is a county located in the U.S. state of Illinois. As of the most recent data available, the county has a population of approximately 17,008 people, with a population density of about 33.88 persons per square mile.
The county spans a total land area of 502.00 square miles (1,300.00 square kilometers). The administrative center and county seat is Marshall, which often serves as a hub for local governance and services. The largest city within the county by population is Marshall.
Geographically, Clark County experiences varied elevations, with its highest point at Westfield 760 ft and its lowest point at Martinsville 610 ft. The region operates in the UTC-6.