Castle West of the graveyard, beside the shannon, are the remains of a strong castle of the 13th century. Not much is known of its history, but it was probably built by the Justiciar, John de grey, Bishop of Norwich of about the same time as Athlone Castle, to guard the line of the shannon.
The earthworks on which it stands are still steep and formidable. The rectangular stone keep with a courtyard on the north side towards the river are placed on a motte or mound with a large square annexe surrounded by a deep fosse, probably intended to be water filled.
	The castle has been slighted (deliberately destroyed to make it unusuable) possibly in the 17th century so that portions of its very thick wall lean out at an angle. There is a local ledgend that if 7 redheads go up to the castle at the same time the castle will fall.