By the mid-18th century, a few American and French fur traders engaged historic Native American tribes in present-day Ohio in the fur trade. The Native Americans had their own extensive trading networks across the continent before the Europeans arrived. American settlement in the Ohio Country came after the American Revolutionary War and the formation of the United States, with its takeover of former British territory. Congress prohibited slavery in the Northwest Territory which presaged Ohio and the five states of the Territory entering the Union as free states. Ohio's population increased rapidly after United States victory in the Northwest Indian Wars brought peace to the Ohio frontier. In 1803, Ohio was admitted to the union as the 17th state. Settlement was chiefly by migrants from New England, New York and Pennsylvania. Southerners settled along the southern part of the territory, arriving by travel along the Ohio River from the Upper South. Yankees, especially in the "Western reserve" (near Cleveland), supported modernization, public education, and anti-slavery policies. The state supported the Union in the American Civil War, although antiwar Copperhead sentiment was strong in southern settlements.
After the Civil War, Ohio developed as a major industrial state. Ships traveled the Great Lakes to deliver iron ore and other products from western areas. This was also a route for exports, as were the railroads. In the late 19th and early 20th centuries, the fast-growing industries created jobs that employed hundreds of thousands of immigrants from Europe. In World War I Europe was closed off to passenger traffic. A new wave of migrants came from the South, with rural whites from Appalachia, and African Americans in the Great Migration from the Deep South, to escape Jim Crow and violence.
The cultures of Ohio's major cities became much more diverse with the traditions, cultures, foods, and music of the new arrivals. Ohio's industries were integral to American industrial power in the 20th century. In the later 20th century, economic restructuring in steel, railroads, and other heavy manufacturing cost the state many jobs as heavy industry declined. The economy in the 21st century has gradually shifted to depend on service industries such as medicine and education
