In fields north of the town lie impressive ruins of a rectangular royal castle of c1270 with U-shaped towers at the corners and on either side of the gateway passage.
The plan resembles that of the slightly later castle of Harlech in North Wales. The Elizabethan windows date from the 1580s, when the castle was remodelled as the seat of the governer of the province of Connacht.
Ballymote in Sligo is similar in layout and impressiveness but is unfortunately kept locked up, whilst the larger Ballintober in Roscommon is fragmentary. An earlier enclosure castle at Limerick with a gatehouse and round towers has been spoiled by a monstrous new museum building.