Following the first land sales under the Land Ordinance of 1785, the federal government began to permit land companies to purchase huge areas farther down the Ohio River. The U.S. Congress then passed the Northwest Ordinance of 1787 to provide government of the region. The law stated that no fewer than three nor more than five states would be formed from the region. Also set out was the procedure for creating these states. Ohio was the first state admitted to the Union (1803) under the provision. British trading posts in the region were a challenge to U.S. control, which was not firmly established until after the War of 1812.