 According to the United States Census Bureau, the township has a total area of 47.3 square miles (122.5 km²), of which, 47.3 square miles (122.4 km²) of it is land and 0.02% is water.Union Township is bordered by Ward Township to the north, Bradford County to the east, Lycoming County to the south and Liberty and Hamilton Townships to the west.As of the census of 2000, there were 945 people, 343 households, and 282 families residing in the township.