According to the Environmental Protection Agency, there are an estimated 12,000 lakes in the Republic of Ireland, covering an area of more than 1,200 square kilometres.
The list below contains only those loughs that are of geographic, geological, or historical importance and almost all of them are over a square kilometre in area.
Those partly or wholly within Northern Ireland are marked with an asterisk (*).
Most of the Republic of Ireland lake areas are taken from the Environmental Protection Agency's A Reference based Typology and Ecological Assessment System for Irish Lakes (pp.
10–13)[20] An example of a brackish lagoon is Lady's Island Lake, County Wexford