| Official Name: | Mark Township, Defiance County, Ohio |
| Settlement Type: | Township |
| Mapsize: | 250px |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Ohio |
| Subdivision Type2: | County |
| Subdivision Name2: | Defiance |
| Unit Pref: | Imperial |
| Area Total Km2: | 94.9 |
| Area Land Km2: | 94.9 |
| Area Water Km2: | 0.0 |
| Population As Of: | 2020 |
| Population Footnotes: | [1] |
| Population Total: | 902 |
| Population Density Km2: | auto |
| Population Density Sq Mi: | auto |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Footnotes: | [2] |
| Elevation M: | 221 |
| Elevation Ft: | 725 |
| Coordinates: | 41.2911°N -84.6292°W |
| Blank Name: | FIPS code |
| Blank Info: | 39-47852[3] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 1086035 |
Mark Township is one of the twelve townships of Defiance County, Ohio, United States. The 2020 census found 902 people in the township.
Located in the southwestern part of the county, it borders the following townships:
No municipalities are located in Mark Township, although the unincorporated community of Mark Center is located in the township's center.
Mark Township was established in 1851, and named for Mark Kenton, an early settler.[4] It is the only Mark Township 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. Two are elected in the year after the presidential election and one is elected in the year before it. 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. Vacancies in the fiscal officership or on the board of trustees are filled by the remaining trustees.
The most important highway in Mark Township is State Route 18, which travels from east to west through the center of the township.[7]