Castletown Geoghegan (Irish: Baile Chaisleáin na nGeochagán) in County Westmeath, Ireland, lies south west of Lough Ennell near the county town of Mullingar. Castletown was the seat of the Geoghegan family of the medieval Barony of Moycashel, County Westmeath. The family were descendants of the Southern Ui Neill. They were major landholders in south Westmeath prior to the War of the Three Kingdoms. They lost considerable portion their estates through the confiscation and resettlement acts of the late 17th century. Lilliput, on the shores of Lough Ennel is in Dysart, a neighbouring village approximately 3 miles from Castletown Geoghegan. Nearby Middleton Park House, a magnificent 19th century Georgian house and estate, is now open to the general public.