Prison

Prison, institution for confining people convicted of breaking a law. There are three types of prisons in the United States: jails and lockups, run by city and county governments mainly for those awaiting trial; state prisons, operated by the individual states containing the majority of convicted criminals, and federal prisons, which house society's most violent offenders and those who break federal laws. By the early 20th century imprisonment had replaced corporal punishment, capital punishment, and exile as the chief method of dealing with criminals. The purpose of prisons is threefold: to punish the wrongdoer; to protect society; and to act as a deterrent. Overpopulation is a serious problem in modern prisons, leading to the 1981 Supreme Court ruling that two prisoners may be kept in a cell built for one if prison conditions on the whole are humane. At the end of 1989 U.S. federal and state prisons held about 710,000 inmates; nearly 0.3% of the U.S. population.