On February 12, 1820, the Ohio government authorized the creation of Williams County. Residents named the county in honor of David Williams, a hero of the American Revolution. Williams helped capture Major Jean André, a British officer who attempted to help the infamous American traitor Benedict Arnold surrender West Point to the British, and was later hanged by the Continental Army during the American Revolution after it was discovered he was a spy. Williams County was originally part of territory set aside for Ohio's Indian people by the Treaty of Greenville. The land comprising this county also came under dispute between Ohio and Michigan during the "Toledo War."
Williams County is located in the northwestern part of Ohio. Its western border helps form the boundary between Ohio and Indiana, and its northern border helps form the boundary between Ohio and Michigan. The county seat is Bryan, which is the largest community in the county, with a population of 8,333 people in 2000. Just over one percent of the county's 422 square miles are deemed to be urban. The county averages ninety-three people living in each square mile. Between 1990 and 2000, the county experienced a six percent increase in population. This is unusual for Ohio's more rural counties, as residents usually seek better opportunities in the state's larger cities. In 2000, the county's residents numbered 39,188 people.
Most of Williams County's residents find employment in agricultural positions, with seventy-five percent of the county's acreage under cultivation. Manufacturing, retail, and service positions finish second, third, and fourth respectively. In 1999, the county's per capita income was 25,226 dollars, with 6.8 percent of the county's residents living below the poverty level.
Most voters in Williams County claim to be independents, yet in recent years, they have overwhelmingly supported Republican Party candidates at the national level.