The 2020 census found 43,796 people in the township, 35,999 of whom lived in the city of Marion.

Located in the center of the county, it borders the following townships: Most of the city of Marion, the county seat of Marion County, is located in central Marion Township.

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.