County Mayo (Irish: Contae Mhaigh Eo, meaning "Plain of the yew trees") is a county in Ireland. In the West of Ireland, in the province of Connacht, it is named after the village of Mayo, now generally known as Mayo Abbey. Mayo County Council is the local authority. The population was 137,231 at the 2022 census. The boundaries of the county, which was formed in 1585, reflect the Mac William Íochtar lordship at that time.