The Northwest Ordinance became law on July 13, 1787.
Officially titled An Ordinance for the Government of the Territory of the United States, North-West of the River Ohio, it created the Northwest Territory. The territory covered lands between the Ohio River, the Mississippi River, the Great Lakes, and Pennsylvania. Its later states included Ohio, Indiana, Illinois, Michigan, Wisconsin, and part of Minnesota.
The ordinance established a process through which territories could become states, rather than simply expanding the boundaries of existing states. It also protected religious freedom, trial by jury, habeas corpus, and public education in the territory. A major provision prohibited slavery in the Northwest Territory, although it did not immediately free enslaved people already held there.
The Confederation Congress passed the measure while the Articles of Confederation still governed the nation. The First Congress reaffirmed it in 1789 with modifications. Its territorial framework became an important model for later American westward expansion.