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.

Bryan is a city in, and the county seat of, Williams County, Ohio, United States. It is located in the state's northwestern corner, 53 miles (85 km) southwest of Toledo. The population was 8,729 at the 2020 census.