Salem Township is one of the eleven townships of Warren County, Ohio, United States, located in the central part of the county. The 2000 census found 4,133 people in the township, up slightly from the 4,038 in 1990; of this total, 2,847 lived in the unincorporated portions of the township. It is the second smallest township in the county with 13,459 acres (54 km²). It is one of fourteen Salem Townships statewide.