Located in the southwestern corner of the county, it borders the following townships: Harrison Township lies farther west than any other location in Vinton County.

No municipalities are located in Harrison Township, although the unincorporated community of Ray lies in the township's southeast.

It is one of nineteen Harrison Townships statewide.

[4] The township is governed by a three-member board of trustees, who are elected in November of odd-numbered years to a four-year term beginning on the following January 1.

There is also an elected township fiscal officer,[5] who serves a four-year term beginning on April 1 of the year after the election, which is held in November of the year before the presidential election.