Menard Correctional Center, known prior to 1970 as Southern Illinois Penitentiary, is an Illinois state prison located in the town of Chester in Randolph County, Illinois. It houses maximum-security and high medium-security adult males. The average daily population as of 2007 is 3,410. Menard Correctional Center's average prisoner age is 34 years old. Each inmate's average annual cost totals as of fiscal year 2018 $27,364.