According to the United States Census Bureau, the township has a total area of 50.9 square miles (131.8 km²), of which, 50.8 square miles (131.6 km²) of it is land and 0.1 square miles (0.2 km²) of it (0.14%) is water.
Richmond Township is bordered by Tioga Township to the north, Rutland Township to the north and east, Sullivan Township to the east, Covington Township to the south and Charleston and Middlebury Townships to the west.