This lake was one of the first freshwater lakes to obtain a Blue Flag. This very popular for swimming and jumping off the pier in the summer time. (So a lot of muggles!)
There are three islands on the lake, Nun's Island, Castle Island and Turgesius Island. On Nun's Island there was once a convent, which gave the name of the town of Collinstown, Baile na gCailleach, meaning the town of the old hags or the veiled women. One Castle Island there was an ancient bell, which is now in the National Museum of Ireland.
The cache is located close to the shores of the lake, giving you a great view of the lake!