Sligo is a coastal seaport and the county town of County Sligo, Ireland, within the western province of Connacht. With a population of 20,60…Sligo is a coastal seaport and the county town of County Sligo, Ireland, within the western province of Connacht. With a population of 20,608 in 2022, it is the county's largest urban centre and the 24th largest in the Republic of Ireland.