Monroe Township is one of twenty townships in Benton County, Iowa, United States. As of the 2000 census, its population was 259.
Monroe Township was founded in 1851.
According to the United States Census Bureau, Monroe Township covers an area of 36.31 square miles (94.04 square kilometers); of this, 36.3 square miles (94.01 square kilometers, 99.97 percent) is land and 0.01 square miles (0.03 square kilometers, 0.03 percent) is water.
The township contains these four cemeteries: Gnagy, Ramthun, Saint Joseph and Urmy.