Some admissions are for a few hours. Other pre-trial detainees are held for several years awaiting their trial. Jails must be able to accommodate all arrestees from those charged with misdemeanors to violent criminal offenders. For that reason, most jails are designed as maximum custody facilities. Jails must provide all ranges of medical and mental health services, and be able to handle any medical emergency.
Jails operate work release programs, boot camps, and other specialized services.
They try to address education needs, substance abuse needs, and vocational needs while managing inmate behavior. Inmate idleness contributes to management problems. There are approximately 3,600 jails in the United States. The number of beds in the entire system currently is 3,730. The average daily population is 4,300.