Castletown is a village in County Laois. Castletown is known as “The Tidiest Village in Laois”. Chairman of the Tidy Towns committee is Seán Fleming, TD. Not only is Castletown the Tidiest Village in Laois but in 1998, Castletown were just four points behind the national winner. They won the overall Irish Tidy Towns Competition in 2002.
The older Irish name for the town was Baile Chaisleáin Ua bhFoirchealláin (meaning "castle-town of Uí Fhoirchealláin"). This has been anglicised as Ballycashlan-Offerillan and Ballycaslane-Offeralane. Uí Fhoirchealláin is the name of the parish and was added to distinguish it from another Castletown. According to an extract from a Topographical Dictionary of Ireland, by Samuel Lewis, London, 1837, Castletown was "a village in the Parish of Offerlane, barony of Upper Ossory, Queen’s county, and province of Leinster, 1 3/4 miles (S.by W.) from Mountrath; containing 367 inhabitants. It takes its name from an ancient castle, occupying a commanding situation on the bank of the River Nore, and which, in the early part of the 16th century, was garrisoned by Sir Oliver Norris, son-in-law of the Earl of Ormonde, with a view to curb the power of the Fitzpatricks, to whom it was afterwards relinquished." The extract continues “the village is pleasantly situated on the river Nore, and on the road from Dublin to Limerick, it contains 59 houses, many of which are good residences, and the whole has an appearance of neatness and respectability”.