Ohio Company, the name of two companies organized for the purpose of settling the Ohio Valley.

The First Company

was founded by Virginia planters in 1747 and was granted 200,000 acres (81,000 hectares) of land west of the Allegheny Mountains. Fur traders were employed, and Christopher Gist was sent to explore the area and plan for settlement. By the Treaty of Logstown in 1752, the Iroquois and Delaware Indians granted the company permission to make settlements south of the Ohio River and to build two forts on the river. Gist founded a settlement some 35 miles (56 km) southeast of the forks of the Ohio on the Youghiogheny River, and a trade-goods storehouse was built on the Monongahela River.

The French, who held a monopoly on fur trade in the Ohio Valley, quickly built a fort on the Allegheny River, and indicated they would resist English encroachment. When in 1754 the Ohio Company and the governor of Virginia began building a fort at the forks of the Ohio, the French seized the site, an incident that marked the beginning of the French and Indian War. After the war Great Britain closed the area to settlement.

The Second Company,

known as the Ohio Company of Associates, was formed in 1786 by a group of Revolutionary War officers. Leading figures in the enterprise were two New Englanders, General Rufus Putnam and the Reverend Manasseh Cutler. The company arranged to buy from the United States a tract of 1,500,000 acres (600,000 hectares) north of the Ohio River. (The size of the purchase was later reduced due to lack of funds.) Plans for settling the company's land were a major influence in enactment of the Ordinance of 1787, which provided government for the Northwest Territory. Marietta, Ohio, founded in 1788, was the first of many settlements established by the company.