Geocharax is a genus of crayfish in the family Parastacidae with two described species, both found in southeastern Australia.Geocharax falcata is endemic to the Northern Grampians in Victoria. This species can be found in the headwaters of the Glenelg River and also throughout the north of the Grampians National Park in southwest Victoria. Geocharax tasmanicus is endemic to both Victoria and Tasmania. Within Tasmania, this species is restricted to the far northwest, occurring between Rocky Cape and Temma on the Tasmanian mainland and also on the King Island and the Hunter Island Group. In Victoria, it is restricted to the Otway Region.