Located in a Convent that used to house the Poor Clare order of nuns, it's well worth spending an hour or so wandering around the various exhibits.
Whether you're interested in prehistoric Cavan, the Famine, Folklife, Percy French (the famous song-writer), Medieval Life, or the GAA, you can learn more about these, plus other aspects of the county. The exhibits are laid out over several floors in cosy rooms leading off each other. When we visited, there was also an art exhibition on the top floor.
Some of my "highlights" of the museum:
listening to recordings of locals' memories of the Great Blizzard of 1947; the Corleck Stone (an enigmatic 3-faced Celtic stone); the Folklife Gallery; the Ralaghan figure (a bronze-age figure carved from Yew) and the collection of Sheela-na-gigs.
For younger children, there's a great little playground next to the car park.
Location: The museum is located in Ballyjamesduff on the Virginia road. (Do "not" go looking for it in the lanes south of Ballyjamesduff, as we did. It is incorrectly marked on the OS Road Atlas of Ireland!!)