Randolph County is a county located in the U.S. state of Illinois. According to the 2010 census, it had a population of 33,476. Its county seat is Chester. Owing to its role in the state's history, the county motto is "Where Illinois Began." It contains the historically important village of Kaskaskia, Illinois's first capital. The county is part of Southern Illinois in the southern portion of the state known locally as "Little Egypt", and includes fertile river flats, part of the American Bottom; it is near the Greater St. Louis area.