 According to the United States Census Bureau, the township has a total area of 42.3 square miles (109.6 km²), of which, 42.2 square miles (109.3 km²) of it is land and 0.1 square miles (0.3 km²) of it (0.26%) is water.Sullivan Township is bordered by Rutland Township to the north, Bradford County to the east, Ward Township to the south and Covington and Richmond Townships to the west.As of the census of 2000, there were 1,322 people, 487 households, and 392 families residing in the township.