County Mayo (Irish: Contae Mhaigh Eo) is a county in Ireland. It is located in the West Region and is also part of the province of Connacht. It is named after the village of Mayo, which is now generally known as Mayo Abbey. Mayo County Council is the local authority for the county. The population of the county is 130,552 according to the 2011 census. The county was formed in 1585, and its boundaries reflect the Mac William Íochtar lordship at that time.