The Tatsho Mountain occurrence is centred on a limestone outcrop on the north side of Tatsho Mountain, about 2 kilometres west of the community of Dease Lake.

A mass of limestone of the Upper Triassic Sinwa Formation (Stuhini Group) extends westward from near the south end of Dease Lake across the north slope of Tatsho Mountain. The mass is in fault contact with Upper Triassic Stuhini Group volcanic rocks to the south.