The Jail System
Illinois has 102 counties. According to surveys completed in 2013, there are 102 jail and adult detention facilities, with a population of 20,600 inmates.
The Prison System
As of December 31, 2015, the Illinois prison population was 46,240. The Illinois Department of Corrections operates 25 adult correctional centers, employs approximately 11,600 staff members and had a budget of $1.41 billion in FY2015.
The Community Corrections System
As of Dec. 31, 2014, there were 122,184 adults on probation. In FY2015, the Department of Corrections supervised 28,478 parolees.