Nippenose Township is on the south shore of the West Branch Susquehanna River in western Lycoming County.
According to the United States Census Bureau, the township has a total area of 11.2 square miles (29.1 km2).10.7 square miles (27.7 km2) of it is land and 0.5 square miles (1.4 km2) of it (4.81%) is water.