The Preston School of Industry, also known as Preston Castle, was formerly one of the oldest and best-known reform schools in the United States. It is located in Ione, California, in Amador County. After construction was finished in 1890, the institution was opened in June 1894 when seven wards (minors under the guardianship of the state, but not necessarily juvenile offenders), were transferred there from San Quentin State Prison. The original building, known colloquially as "Preston Castle" (or simply "The Castle"), is the most significant example of Romanesque Revival architecture in the Mother Lode. It was vacated in 1960, shortly after new buildings had been constructed to replace it. The abandoned building has since been named a California Historical Landmark and is listed on the National Register of Historic Places. In 1999, the institution's official name was changed to the "Preston Youth Correctional Facility". The California Department of Corrections and Rehabilitation announced on October 21, 2010, that the Preston Youth Correctional Facility was to close,[4] and a closing ceremony was held on June 2, 2011.