The Old Northwest is another name for the Northwest Territory—the region around the Great Lakes and between the Ohio and Mississippi rivers. Consisting of about 248,000 square miles (642,000 square kilometers), the territory was acquired by the United States after its victory in the American Revolution (1775–1783). Britain ceded the region in the Treaty of Paris of 1783, which ended the fighting, and the region officially became known as the Territory Northwest of the River Ohio. (Eastern seaboard states also claimed parts of the territory, but those claims were settled by the late 1700s.)
Development of territory was helped by the completion of New York's Erie Canal in 1825. The east-west waterway ran from Albany to Buffalo, connecting the Hudson River (which flows into the Atlantic Ocean) to Lake Erie (one of the Great Lakes). The canal linked the Old Northwest with the established states to the east and promoted the settlement of the territory, mostly by farmers.
Steamboats (invented in 1807) and railroads (introduced to the United States in 1831) also encouraged development of the region. Pittsburgh, Cincinnati, Louisville, Detroit, and Chicago became commercial centers. Out of the Old Northwest the states of Ohio (admitted as a state 1803), Indiana (1816), Illinois (1818), Michigan (1837), and Wisconsin (1848) were created, and part of the former territory was used to form present-day Minnesota (1858).
See also: Erie Canal, Expansionists, Illinois, Indiana, Michigan, Minnesota, Ohio, Railroads, Steamboats, Wisconsin