The 2020 census found 618 people in the township.

Located in the eastern part of the county, it borders the following townships: The village of Summerfield, the second largest village in Noble County, is located in southwestern Marion 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.