The St. Louis County Jail is a direct-supervision facility that detains adults and juveniles being tried as adults who are awaiting trial or serving county sentences and is the only jail in Missouri that holds an accreditation known as the ALDF from the American Correctional Association (ACA).

After Clayton, Missouri was chosen as the permanent county seat, a courthouse and jail were built in December 1878.

By 1945, a bond issue allowed for the construction of a new courthouse and jail in Clayton facing Forsyth Boulevard that was completed in 1949.

Because land costs in Clayton were considered prohibitive, the new Adult Correctional Institution was built in 1969 in Gumbo, a historical community which was located in present-day Chesterfield, Missouri approximately 15 miles (24 km) to the west.

[1] George "Buzz" Westfall was the St. Louis County Executive from 1990 to October 2003 when he died after developing a staph infection.

The cells in St. Louis County Jail do not have bars, instead the floor plan is laid out in a dormitory fashion.

The outer door is controlled by a permanent staff member who mans a desk in the convergence area of the floor.

The St. Louis County Jail uses a direct-supervision management philosophy in the main inmate housing areas.

Response times as well as the number of staff responding varies, as there is usually no more than 2 extra officers per floor and a maximum of 4 operating internal elevators.