On the outskirts of Mansfield, Ohio sits the imposing remains of the defunct Ohio State Reformatory — also known as the Mansfield Reformatory—which was in operation from 1896 until a federal order (following a prisoners’ class action lawsuit alleging inhumane conditions) closed it for good in 1990. OSR began as a rehabilitation-oriented facility largely for non-violent offenders, but after a devastating 1930 fire at the Ohio Penitentiary in Columbus, about 70 miles to the south, that killed more than 300 inmates, hundreds of murderers, rapists and other hardcore, violent prisoners were transferred to OSR, turning the place into a more punitive, forbidding (and intensely overcrowded) institution.

After OSR was shuttered, the steady deterioration of its innards commenced, although the facility gained notoriety for serving as the prison in the 1994 film The Shawshank Redemption and, a few years later, as the Russian prison in 1997's Air Force One (aside from a handful of film production artifacts in one or two museum-type chambers, however, everything inside OSR is real and left basically as it was during the years the prison was in operation). The prison is also notable for its East Cell Block —six tiers high, it’s the world’s largest free-standing steel cellblock. For the first several decades of its existence, wardens and their families lived inside the prison, making for an interesting contrast between the once-well-appointed family/administrative areas and the cellblocks and other inmate areas — all contained within OSR’s gothic, castle-like walls.

These days, the Mansfield Reformatory Preservation Society oversees the property, and is involved in the slow process of cleaning and restoring various parts of the prison—or at least keeping sections of it from disintegrating entirely—which they fund via donations and by allowing individuals and small groups inside for guided historical tours and, if you like, to have the run of the place until closing hours to shoot photographs (some nights they also do ghost tours, as it’s said OSR is one of the most haunted places in America, if you believe in that sort of thing).

It’s a fascinating and affecting place, one that you can easily spend all day exploring. The following are photos from my recent visit to OSR.

Michael Alan Goldberg is an award-winning crime reporter, photographer and occasional music journalist based near Philadelphia, PA. Follow him on Twitter @mg_thereporter.