Castlebar, market and county town, County Mayo, Ireland, at the head of Lough (lake) Castlebar. The town was founded early in the 17th century and was incorporated in 1613. The administrative seat of the county and a fast-growing town, it is an active market area and tourism centre, popular with walkers, shoppers, and anglers alike; the scenic Lough Lannagh, the Mayo Peace Park, and National Museum of Country Life are popular attractions. Active sports in Castlebar include hurling, Gaelic football, soccer, rugby, and golf. The town houses the Mayo campus of Atlantic Technological University and hosts several popular festivals, including the International Four Days Walks, The Blues Festival, and Heritage Day. Famous people born in Castlebar include Irish prime ministers Charles Haughey and Enda Kenny and popular novelist Sally Rooney. Pop. (2006) 10,655; (2011) 10,826.