prison, place of confinement for the punishment and rehabilitation of criminals. By the end of the 18th cent. imprisonment was the chief mode of punishment for all but capital crimes. At that time, largely as a result of the writings of Cesare Beccaria in Italy and John Howard and others in England, there was a wave of penal reform and improvement in conditions. The earliest North American reform centered in Philadelphia (1790) and in Auburn, N.Y., where systems of solitary confinement and congregate labor were introduced. These penitentiaries required the prisoners to maintain absolute silence. Reform efforts continued through the 19th cent., with two notable women (Elizabeth Fry and Dorothea Dix) among the reformers. British and Irish influences led to the practice of parole.
In the 20th cent. efforts were made in the United States to eliminate unsanitary and demoralizing prison conditions. Reforms included the individualization of treatment, psychiatric assistance, constructive labor and vocational training (see convict labor), professionalization of correctional officers, and the introduction of work release programs. In some places, however, corporal punishment is still used. Until the late 1970s, there was a growing tendency to regard the basic aim of imprisonment as rehabilitation of the criminal rather than as punishment or protection of society. That trend, however, has been reversed. Correspondingly the length of sentences has been extended, and the number of inmates increased substantially. From 1980 to 1990, the nation's federal and state prison population increased by 134% to 771,243 persons; by 2000 it was 1,381,892 persons, a 79% increase from 1990. From 1970 to 2000 the number of state inmates alone increased 500%. By 2005 the prison population appeared to be growing more slowly; some 1,446,269 persons were in federal and state prisons, only a 4.6% increase from 2000, due mainly to a slowing in the growth of the state prison population. Prison population peaked at 1,615,487 inmates in 2009; since then it has gradually decreased. In 2005 an additional 874,090 persons were in local jails and other facilities; the local inmate population increased by 20% from 2000 to 2005. The increase in the number of inmates contributed to a fall in the crime rate, but increased sentences and other penalties appear not to have acted as a deterrent to crime among released inmates, who have become slightly more likely to be rearrested on average.
The chief types of prisons in the United States (with similar institutions in other countries) are the local jail, for pretrial detention and short sentences, and the state and federal penitentiaries, for convicts with long sentences. Special penal institutions are provided for juveniles, the sick, and the criminally insane. The rapid increase in prison population has led some U.S. jurisdictions to explore letting private contractors operate prisons. These private prisons increased from one or two in the mid-1980s to more than 150 by the end of the century. Some of these institutions proved problematic, often because they were not subject to government regulation or because they took in out-of-state prisoners. Juvenile delinquents are usually sent to reformatories or other correctional institutions. In the face of growing U.S. youth crime from the 1970s to the 90s, military-style "boot camps" for juvenile offenders were widely instituted. Many of these were subsequently criticized for brutality and high recidivist rates, and some were scaled back or closed. Among famous prisons in history are the Bastille in Paris and the Tower of London. In the United States, Sing Sing (see Ossining) and Alcatraz (now closed) are the two best known.
See D. J. Rothman, The Discovery of the Asylum (1971) and Conscience and Convenience (1980); M. Foucault, Discipline and Punish (tr. 1979); D. C. Anderson, Crimes of Justice (1988) and Sensible Justice (1998); E. Currie, Crime and Punishment in America (1998); B. Western, Punishment and Inequality in America (2006); G. C. Loury et al., Race, Incarceration, and American Values (2008).