Roscommon Castle (RO039-043001-) is a National Monument in the guardianship of the State, located in the townland of Cloonbrackna. One of the most important royal castles in Ireland during the late 13th and early 14th centuries, it was built to a design similar to contemporary royal castles such as Harlech Castle in Wales. Roscommon Castle was commenced by the Crown in 1269 and was originally occupied by Robert de Ufford, Lord Justice of Ireland.
In its early days it was attacked and burned several times by Gaelic forces before construction was completed in 1290. These works included the construction of a curtain wall around the castle and a large twin towered gatehouse. During the 15th century possession moved between various factions of the O’Conor’s. In 1577 the castle was granted to Sir Nicholas Malby (Governor of Connaught), who kept a force of 50 foot soldiers stationed within it. Malby transformed the castle into an imposing, four-storey Renaissance-style house. From 1645 to 1652 the castle was occupied by Confederate Catholics, but was dismantled after surrendering to the Cromwellians.
Further details are available on the ASI mapviewer; search by SMR RO039-043001-