The United States adopted the Northwest Ordinance in 1787.
The Confederation Congress approved the Northwest Ordinance on July 13, 1787. It organized the territory northwest of the Ohio River and established a process by which territories could become states. The region eventually produced the states of Ohio, Indiana, Illinois, Michigan, Wisconsin, and part of Minnesota.
The ordinance set population thresholds for territorial government and eventual statehood. It also protected certain civil liberties, encouraged public education, and prohibited slavery in the Northwest Territory. Its language became an important model for later territorial policies.
The Northwest Ordinance is sometimes confused with the Land Ordinance of 1785, which primarily established a surveying system for western lands. It is also distinct from the Constitution, drafted later in the same year. Together, these measures showed how the United States attempted to govern expansion even before the new Constitution took effect.