 Rich Valley Township was named for the fertile soil of the Crow River valley.According to the United States Census Bureau, the township has a total area of 36.2 square miles (93.8 km²), of which 36.1 square miles (93.5 km²) of it is land and 0.1 square miles (0.3 km²) of it (0.33%) is water.As of the census of 2000, there were 727 people, 263 households, and 206 families residing in the township.