Lough Gur is a lake in County Limerick, Ireland. The lake forms a horseshoe shape at the base of a hill and some rugged elevated countryside.

The area is renowned for the long history of human settlement in the area. Ruins from the stone-age in particular are abundant around the lake. The largest stone circle in Ireland, at Grange is located near the lake. The remains of at least three crannogs are present, and remains of stone-age houses have been unearthed (the house outlines are known as "the spectacles"). A number of ring forts is found in the area, with one (a hill fort) sitting atop the hill that overlooks the lake. Some are Irish national monuments .

A visitors' centre is open beside Lough Gur, along with a carpark and picnic area. The location is pleasant, particularly in the summer months. A gradual shore-line is present at the visitor area, with a shallow section of lake reaching up to the maintained lawn. As a result, the area is often used for watersports. Motorised craft are banned on the lake.

A castle is present, though not open to visitors, near the entrance to the carpark. It lies at the neck of the peninsula around which the lake washes. There is some other architecture dating from more recent times, with the ruins of an early Christian church by the road leading down to the lake, and another castle situated at the other side of the peninsula.

See also: Early history of Ireland, List of Irish loughs and lochs