The centre, which also operates the Tipperary North Genealogical Service, is housed in the former gaol (1842). The gatehouse contains the condemned cells and the execution chamber, with the portraits and biographical notes of the 17 men executed in t..

The circular keep (30m high), once part of the curtain walls, and a vast 13C hall (restored) are what remains of the fine Anglo-Norman castle, built around 1200.