United States Penitentiary, Marion
| Location | Southern Precinct, Williamson County, near Marion, Illinois |
|---|---|
| Coordinates | 37°39′47″N 88°59′3″W / 37.66306°N 88.98417°W |
| Status | Operational |
| Security class | Medium-security (with minimum-security prison camp) |
| Population | 1,298 [1,117 at the USP, 181 in prison camp] (September 2023) |
| Opened | 1963 |
| Managed by | Federal Bureau of Prisons |
| Warden | Daniel Sproul |
The United States Penitentiary, Marion (USP Marion) is a large medium-security United States federal prison for male inmates in Southern Precinct, unincorporated Williamson County, Illinois. It is operated by the Federal Bureau of Prisons, a division of the United States Department of Justice. The facility also has an adjacent satellite prison camp that houses minimum security male offenders.
USP Marion in Southern Illinois is approximately 9 miles (14 km) south of the city of Marion, Illinois, 300 miles (480 km) south of Chicago, and 120 miles (190 km) southeast of St. Louis, Missouri.