Glencar Lough locally known as Glencar Lake, is a freshwater lake in the northwest of Ireland. It covers an area of 1.15 square kilometres (0.4 sq miles) and lies mostly in County Leitrim with a smaller part in County Sligo. Glencar Waterfall is located near the lake's north shore on the Leitrim side. This popular viewpoint of the lake is situated in County Leitrim although most of the scene in view is in County Sligo.