The Old Idaho Penitentiary State Historical Site was a functioning prison for 101 years.
It was built in 1870 and the first prisoners were brought in 1872. The buildings on the site
were built by inmate laborers.

The Old Idaho Penitentiary grew from a single cell house into a complex of several buildings
holding Idaho's most notorious criminals. The Old Pen received over 13,000 inmates with a
maximum population of 603 inmates. There were 222 women inmates (including repeat offenders.)