There are 101 Probation Departments in Illinois, serving a population of 12,854,526 people in an area of 55,505 square miles. There is 1 Probation Department per 127,272 people, and 1 Probation Department per 549 square miles.
The state of Illinois is ranked 21st in Probation Departments per capita, and 5th in Probation Departments per square mile.