Castlebar is the county town of County Mayo, Ireland. It is in the middle of the county and is its largest town by population. Castlebar's population boomed in the late 1990s, rising by one-third in six years, though this growth has slowed in recent years. According to the 2011 Census it stands at 10,826 inhabitants.
A campus of Galway-Mayo Institute of Technology and the Country Life section of the National Museum of Ireland are two important local amenities. The town is linked by railway to Dublin, Westport and Ballina. The town is surrounded by several villages, with Breaffy the most well known. The main route by road is the N5. Its economy is primarily service-based.