One of the most famous Idaho Penitentiary inhabitants wore a black-and-white uniform.
He roamed the prison yard like he owned it, encouraging prisoners to steal food for him from the butcher shop and bakery. Prison guards opened doors for him, yielding to his every whim.
This fearsome male, who commanded respect, also stood about 10 inches off the ground.
Dennis the Cat lived at the Pen from 1952 through 1968. Smuggled in by an inmate, the kitten became an open secret.
Upon his death at age 16, Dennis was laid to rest on the Pen grounds, complete with a concrete slab, a stainless-steel plaque engraved in the machine shop, and a slow, steady parade of mourners to visit his grave. Dennis has the only marked grave within prison walls.
His tenure at the Old Idaho Penitentiary was detailed in his obituary, penned by inmate Ed Eline in "The Clock," the inmate-run newspaper. The illustration accompanying the obituary is the only known depiction of Dennis.
“Unlike other documented animal stories within the site’s history, including Zipper, the famed ‘head mouser’ in the Dining Hall, Dennis was more of a pet than a working animal,” Idaho State Historical Society (ISHS) Visitor Services Coordinator Jacey Brain said. “He might even be considered a service animal. That was his job. He was known to possess an empathy that made him gravitate toward life-termers, or those most in need of an animal’s affection. Dennis’ story represents the humanity behind prison walls, and the universal love that people have for other living things.”
Dennis continues to make a lasting impact. Every Memorial Day (anecdotally his birthday), the ISHS holds Dennis the Cat Day.
“The first Dennis the Cat Day in 2021 was a rousing success, and the event has become one of the Old Idaho Penitentiary’s signature programs since then,” Brain said. “Education and community are two pillars of the site’s goals for programming, and we use this opportunity to not only celebrate Dennis, but to tell stories of the other animals that shaped the penitentiary’s story, and the roles that animals have in an institution such as this. We tell stories of hounds, horses, mice, and even a ‘champion’ bullfrog whom the residents rallied around. We also share and support our community partners by raising donations for Simply Cats and the Idaho Humane Society in honor of these storied creatures.”
For more about the Idaho Penitentiary and the next Dennis the Cat Day, visit history.idaho.gov.