A reformatory or reformatory school is a youth detention center, or an adult correctional facility. The term is still in popular use for adult facilities throughout the United States, although most reformatories have been renamed correctional centers (or similar) in recent years. The term reformatory (or reformatory school) was also commonly used during the 19th century throughout the United Kingdom in reference to penal facilities for children under the age of 14. 
The term "reformatory" also has considerable constitutional significance in Canada, as s.92 (6) of the British North America Act exclusively reserves powers over reformatories and prisons to provincial jurisdiction, as well as pre-trial incarceration for those judged unsuitable for bail. In contrast, s. 91 (28) exclusively reserves powers over penitentiaries and criminal legislation to federal jurisdiction creating an intricately overlapping burden of responsibility In some provinces, particularly British Columbia, pre-trial detainees greatly suffer relatively to convicted provincial inmates (or even many federal inmates) . Under current law, most juveniles and anyone sentenced to a term of imprisonment up to and including two years less a day will serve time in a provincial prison or reformatory (although they may be released far earlier due to overcrowding or a determination that further incarceration is unjustified). Controversially, the use of "two years less a day" sentences has been used by some judges to avoid mandatory sentences such as deportation, weapons prohibitions, prohibitions to entry to the USA, or harsh pardon ineligibility barriers.
The use of the terms "prison", "correctional centre", and "reformatory" vary by province and category of offender. In contrast, federal penitentiaries are mostly referred to simply as "institutions". In addition, a person who would face a provincial sentence of incarceration for an offence would face criminal proceedings more directly administered by the province. For example, judges in such proceedings are appointed by the province, rather than superior court justices who are appointed by the federal government (despite most prosecutors, superior court justices, and court costs being paid by the provinces in such cases). Provincial governments also have more leeway to create diversion programs in such cases. Such offences are often prosecuted (if at all) by summary charge and result in relatively minor sentences.
Reformatories in Ontario, Canada
Until 1972, the term reformatory referred to an Ontario provincial prison for either juveniles (16 and 17 years of age) or adults (18 years of age or older). Very often, one reformatory facility would house both. Offenders under the age of 16 were held in Training Schools. After 1972, when Ontario's Department of Correctional Services (having been renamed in 1968 from the Department of Reform Institutions) became the Ministry of Correctional Services, these facilities were officially redesignated as correctional centres.
- Ontario Reformatory-Guelph became Guelph Correctional Centre
- Ontario Reformatory-Mimico became Mimico Correctional Centre
- Andrew Mercer Reformatory for Women was, for a time, renamed The Mercer Complex
- Ohio State Reformatory
- Ohio Reformatory for Women
- Oklahoma State Reformatory
- Kentucky State Reformatory
- Lorton Reformatory
- Reform school
- University of Waterloo, Young Immigrants to Canada (including home children) - Reformatories and Industrial Schools
- "Bradwall Reformatory School 1855 to 1920", a Local History Site. ()