Mount Rittmann is high and lies in the Mountaineer Range. A or wide caldera is located underneath the Aviator Glacier; it is outlined by a ring of volcanic hills and outcrops that emerge from an almost flat surrounding terrain. The name Mt. Rittmann is sometimes applied to a fumarolically active nunatak on the caldera rim. The base of the volcano crops out from the Pilot Glacier, which together with the caldera is one of the few parts of the otherwise snow- and ice-covered volcano that crop out from the ice. Outcrops consist of hyaloclastites, lava flows and pillow lavas.