The MacNamara Clan built many of the castles in County Clare, but Knappogue was their actual residence. A MacNamara lived in the castle almost continuously from 1467 until 1815, almost four hundred years.

The castle consists of a most impressive tower house with later additions in a Neo-Gothic style. The tower house was the keep, and like most tower houses it had arrow slits on the bottom levels and larger windows for the living quarters on the top. The later additions included a garden, clock tower and courtyard. The interior of the castle has lovely Elizabethan fireplaces and beautiful wood paneling.

The castle is privately owned but is managed by Shannon Heritage who has it open to the public.