High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! Salt Rock Township is one of the fifteen townships of Marion County, Ohio, United States. The 2000 census found 699 people in the township, 311 of whom lived in the unincorporated portions of the township. It is the only Salt Rock Township statewide. 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.