The Old Idaho Penitentiary started receiving criminals to its cell blocks, solitary confinement and even gallows back in 1872 – and closed in 1973 due to a rising prison population and outdated conditions. Over the 101-year timespan, Old Pen – as it's sometimes called – housed more than 13,000 inmates. Now listed on the National Register of Historic Places, the prison is open to visitors who wish to learn more about some of its notorious inmates and the harsh prison conditions on a tour.  

Recent visitors recommended watching the short video on the history of the penitentiary on-site, as it gives important context to the rest of the tour. Other travelers warn against bringing young children, as some of the descriptions of the inmates' crimes and executions might be too graphic. Reviewers also praised the tour guides and suggested tagging along on a guided tour, especially since it does not cost extra.

Adult admission to the Old Idaho Penitentiary costs $6; admission for children ages 6 through 12 costs $3. Children 5 and younger can enter for free. Old Pen is open seven days a week. From Memorial Day through Labor Day, it's open from 10 a.m. to 5 p.m., but the rest of the year, it's open from noon to 5 p.m. It's located in Warm Springs, just east of Boise next to the botanical garden, and free parking is available. Visitors can take a free included guided tour of the attraction daily at 10:30 a.m., 12:30 p.m. and 2:30 p.m. Keep in mind, there's also an 18-minute video, which visitors can watch whether they're on a self-guided or guided tour. For more information, visit the Old Idaho Penitentiary's website.