St. Joseph Township is one of the twelve townships of Williams County, Ohio, United States. The 2020 census found 2,666 people in the township.

Williams County is a county located in the U.S. state of Ohio. As of the 2020 census, the population was 37,102. Its county seat is Bryan. The county was created in 1820 and later organized in 1824. It is named for David Williams, one of the captors of John André in the American Revolutionary War.