County town of County Mayo, Republic of Ireland; population (2002) 6,600. Castlebar is an urban district council and is home to Mayo county council. It is the service centre of a large farming area, and has extensive sales of agricultural produce. Its principal industries are health-care products and pharmaceuticals; there is also manufacturers of clothing and electric cable. The district is a centre for fishing, shooting, and tourism.
The town is named after a Norman adventurer named De Barrie, who founded Castle Barry on the site in 1235. The De Burgo clan ruled the area by 1400. In 1609 a market and fair were granted for Castlebar, and four years later King James I granted a charter of incorporation to the town. Castlebar was captured by the Confederate Irish in 1641. It became a garrison town in 1691, and was one of the main British army outposts in Connaught. Planters were moved to the area in the 1770s from Ulster and developed flax-growing and linen industries. During the Rebellion of 1798 the French general Humbert defeated an English force in the town, in a battle known as the Races of Castlebar.
Features include Christchurch Church (1739), which was renovated in 1828; Daly's Hotel (1785), which was originally a coaching inn and retains some of its original features; and the courthouse (1834). Turlough Park House, Castlebar, is home to the National Museum of Folklife, a new addition to the National Museum of Ireland. It was the first branch of the National Museum to open outside Dublin and depicts everyday life during the period 1850–1950.