You can clearly see the several deep holes, the deepest being 112ft in the Lisnabrucka end of the lake. It certainly isn't the bottomless lake of local legend. The large peninsular at the west end of the lake holds the Prison Island, the site of a Crannog, an ancient fortified dwelling.

Sna Beg is the shallow area in the centre, and has a shallow bay running off of it. There is a notable hole in the shallow bay.