According to the United States Census Bureau, the township has a total area of 35.1 square miles (91 km2), all land.

The main geographic featurew of Hersey Township is the Elk Creek which cuts eastward through the county, eventually flowing into the Des Moines River system.

This second Elk Creek flows westward, eventually joining the Big Sioux River system.)

Main highways include: Organization of Hersey Township was approved by the Nobles County Board on May 30, 1872.

Organization occurred shortly after tracks of the St Paul & Sioux City railroad reached Nobles County.

Hersey Township is located in Minnesota's 1st congressional district, represented by Mankato educator Tim Walz, a Democrat.