Before the widespread use of asylums, people with psychiatric conditions were placed in jail. In Kingston, they were placed in the basement of the penitentiary. Rockwood Asylum was built in the mid-1800s. It underwent several name changes over the next hundred years, eventually becoming Kingston Psychiatric Hospital before closing its doors in 1997.
Surrounded by fences, you can’t get very close to the actual hospital, but you can walk around the lovely grounds. Some of the administrative buildings are being used for government services. Although it’s been closed for years, you can see some strange after-hours explorations of the facility on YouTube by people much braver than I.