Located in the western part of the county, it borders the following townships: Two villages are located in Marion Township: Alger in the northwest, and McGuffey in the east.

Marion Township was organized in 1856, and named for Francis Marion, an army officer during the American Revolutionary War.

[4] It is one of twelve Marion Townships statewide.

[5] 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,[6] 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.