The lake measures across at its widest point, while its longest diagonal length measures approximately . Surface area is approximately . Depth measures about . The lake has no
islands. It is connected to
Gold Lake by an unnamed creek. Lakes nearby include
Dreadnought Lake, Little Mud Lake, North Twin Lake and South Twin Lake. The lake has two arms: one located at the southeastern corner and another oriented toward the east-southeast. More precisely, it is in the EL6489 region the Gold Lake region. The EL6489 region includes all of Gold Lake, a majority of Big Ass Lake, and a partition of Little Mud Lake.
Features Big Ass Lake borders
Ship Harbour Long Lake Wilderness Area, which protects of rugged woodlands. A nearby hill, Reid Hill, is situated close to the lake. == Access ==