Which 1787 law established a system for governing U.S. territories northwest of the Ohio River?

The Northwest Ordinance established a system for governing U.S. territories northwest of the Ohio River in 1787.

The Confederation Congress adopted the ordinance on July 13, 1787, while the Constitutional Convention was meeting in Philadelphia. It organized the Northwest Territory, which covered land later associated with states including Ohio, Indiana, Illinois, Michigan, and Wisconsin, as well as part of Minnesota.

The law described a path from territorial government to statehood. It provided for appointed territorial officials at first, elected representation as population grew, and eventual admission of new states on an equal footing with the original states. It also prohibited slavery in the territory, although enforcement and the status of enslaved people remained contested.

The ordinance is sometimes confused with the Land Ordinance of 1785, which established a surveying system for western lands. The Northwest Ordinance dealt primarily with government, statehood, rights, and territorial administration rather than the basic rectangular survey grid.