The 2020 census found 1,478 people in the township.

Located in the southeastern corner of the county, it borders the following townships: Part of the village of Beaver is located in northern Marion Township, and the unincorporated community of Stockdale lies in the southern part of the township.

It is one of twelve Marion 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.