Official Government Website

Dennis the Cat Day

Join the Old Idaho Penitentiary on a Summer Sunday afternoon and discover the story of the Penitentiary’s historic animal mascot, Dennis the Cat during our second annual Dennis the Cat Day!

Activities include Prison Pets history presentations, Prison Paws scavenger hunt and more! Food trucks, beer and alcohol, local pet supply vendors, special presentations, new Dennis merchandise, and more will be available!

Be sure to bring donations of unopened pet food for admission to the Prison Pets history presentations. Donations benefit the Idaho Humane Society and Simply Cats, Boise’s cageless, no-kill, feline adoption center. Presentations take place at 12:30, 1:30, 2:30, 3:30 and 4:30 pm.

Between 1952 and 1968, Dennis lived among the staff and residents of the Idaho State Penitentiary, becoming one of the site’s best liked and most respected figures. Upon Dennis’ death in 1968, the prison population buried him nearby within the main yard, fashioning a durable engraved headstone marking his resting place during his funeral services. Today, guests of the Old Idaho Penitentiary regularly pay their respects at his stone, the only marked grave within the prison walls.

Note: Idaho State Historical Society event registration is non-refundable and non-transferable. Please print or save your email confirmation for proof of registration.


May 29 2022


12:00 pm - 5:00 pm

More Info

Register Now!


Old Idaho Penitentiary
2445 Old Penitentiary Rd., Boise, ID, 83712

Comments are closed.

ver: 3.5.2 | last updated: