[2] It is named after pioneer settler Mellen Smith (1829–1905), who served as the first postmaster at Wallace.

[5] Mellen Township is in southern Menominee County, bordered to the west by the Menominee River, across which is Marinette County in the state of Wisconsin.

U.S. Route 41 crosses the township, leading south 15 miles (24 km) to Menominee, the county seat, and north 26 miles (42 km) to Powers.

According to the United States Census Bureau, the township has a total area of 31.4 square miles (81 km2), of which 30.8 square miles (80 km2) are land and 0.6 square miles (1.6 km2), or 1.80%, are water.

[1] As of the census[3] of 2000, there were 1,260 people, 520 households, and 368 families residing in the township.