Prairie du Rocher is a village in Randolph County, Illinois, United States. Founded in the French colonial period in the American Midwest, the community is located near bluffs that flank the east side of the Mississippi River along the floodplain often called the "American Bottom". The population was 502 at the 2020 census.

Randolph County is a county located in the U.S. state of Illinois. According to the 2020 census, it had a population of 30,163. Its county seat is Chester.