Lough Gur forms a horseshoe shape at the base of Knockdown Hill and some rugged elevated countryside. It is one of Ireland’s most important archaeological sites. Humans have lived near Lough Gur since about 3000 BC and there are numerous megalithic remains there.

Here where low-crowned limestone hills curve through the lough basin, prehistoric people settled on the well-drained sheltered soils… Red deer wandered in the trees alert for the wolf and the bears and for the barking of the hunters’ dogs. At the forest edges, where the land had been cleared, whitebeam, hawthorn and cherry blossomed, white as quartz, in the Springtime…Through the misting rains, the sunshine and the winds of centuries the slow life continued like a stone at the water’s edge while the years drifted by. –Aubrey Burl, 1976

In the past, no minstrel, piper, or poet would willingly spend a night within a mile of [Lough Gur’s] shore, such was its fearful reputation and potency. Even to fall asleep in daytime on its banks was considered among them to be reckless folly. The sense of danger arose from the belief that the original poets of Lough Gur were either descended from, or were demi-gods, like Geároid IarIa, able to draw human poets out of their depths. –Michael Dames, Mythic Ireland, 1992

There is no other spot in Ireland so rich in the evidence of prehistoric habitation and ceremony, and also in the mythic traditions of men and gods. Lough Gur is but 22 km (13.7 miles) from the bustle of the modern city of Limerick, but it stands centuries apart in its symbolic landscape, and millennia distant in its magnificent Bronze Age stone circle, the largest in Ireland. There also are remnants of Neolithic dwellings, artificial islands (crannógs), ruined castles and churches, immense pillar stones, and a wedge tomb that yielded evidence of a ritual sacrifice. All this closely surrounding a scenic lake reputed to harbor a magical realm beneath it.

Lough Gur is today much different than it was in prehistory. Now resembling the open mouth of a dragon, the lake once formed a complete circle, with the present-day Hill of Knockadoon a large island on its eastern side. Drainage schemes in the 1840s resulted in the shape of the lake seen today. The water level was lowered by about 2.4 meters (8 ft) exposing much in the way of archeological treasures, such as the presumed votive offering of a small sword. The lake today is a placid wildlife sanctuary where no motorised watercraft are permitted. The Interpretative Center, located in a reproduction of a Neolithic hut, offers displays and an audiovisual overview of the area.

There is reputed to be a lake-sized version of Atlantis, a sunken city, beneath the waters of Lough Gur. Some have claimed, “When the surface of the lake is smooth, one may see from a boat the drowned city, its walls and castles… Writing in 1812, the credulous French engineer Charles Vallancey said, “It astonished me to see such immense irregular blocks and rocks under water, when nothing similar is to be found in the vicinity.” Wood-Martin suggested in 1895 that such legends might have resulted from folk memories of small homesteads built upon artificial islands in the lake, which later disappeared. There is evidence of at least three of these artificial islands, or crannies, around Lough Gur.