According to Warren Upham, Rockwood Township was probably named after its forests and rocks deposited by glaciers in the Ice Age.

[3] According to the United States Census Bureau, the township has a total area of 34.6 square miles (89.5 km2), all of it land.

As of the census[1] of 2010, there were 390 people, 149 households, and 114 families residing in the township.

There were 166 total housing units at an average density of 4.8/sq mi (1.9/km2).

18.8% of all households were made up of individuals, and 8.7% had someone living alone who was 65 years of age or older.