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The Northwest Territory government authorized the creation of Jefferson County on July 29, 1797. Residents named the county in honor of Thomas Jefferson, the author of the Declaration of Independence and the first United States Secretary of State. Fort Steuben, now the site of Steubenville, contained the first federal land office in Ohio, which sold federal land to settlers as they migrated westward, spurring Ohio�s development.
Jefferson County is located in the eastern portion of Ohio, and it is in the heart of Appalachia. Its eastern border touches the Ohio River and helps form Ohio�s boundary with West Virginia. With only 1.5 percent of the county�s 410 square miles deemed to be urban, most residents live in rural areas. The county averages just over 180 people per square mile. The county�s largest community and county seat is Steubenville, which had just over nineteen thousand residents in 2000. Like many of Ohio�s predominantly rural counties, Jefferson County experienced a loss in population between 1990 and 2000. In 2000, 73,894 people resided in the county, a decrease of eight percent since 1990.
Service industries, such as health care, communications, and tourism, and retail positions are the two largest employers in Jefferson County. Farming is a distant fifth behind manufacturing and government positions. During the late nineteenth and early twentieth centuries, coal mining, especially strip mining, were major employers in the county. Now, much of the strip-mined land has been reforested. In 1999, the per capita income for Jefferson County residents was approximately twenty-one thousand dollars. More than fifteen percent of the county�s residents lived in poverty.
Most voters in Jefferson County claim to be independents, yet in recent years, they have supported Democratic Party candidates by a small margin at the national level.