 According to the United States Census Bureau, the township has a total area of 37.7 square miles (97.5 km²), all of it land.Portage Township is bordered by Keating Township to the north, the borough of Austin to the east and north, Sylvania Township to the east, Wharton Township to the south and east, Cameron County to the southwest and McKean County to the west.As of the census of 2000, there were 223 people, 95 households, and 70 families residing in the township.