Harrison Township is one of twenty townships in Benton County, Iowa, United States.

As of the 2000 census, its population was 354.

[1] Harrison Township was founded in 1849.

[2] According to the United States Census Bureau, Harrison Township covers an area of 27.05 square miles (70.07 square kilometers); of this, 26.57 square miles (68.81 square kilometers, 98.2 percent) is land and 0.48 square miles (1.25 square kilometers, 1.78 percent) is water.

The township contains Bear Creek Cemetery.