Which 1787 law organized the first U.S. territory north of the Ohio River?

The Northwest Ordinance organized the first U.S. territory north of the Ohio River in 1787.

Adopted by the Congress of the Confederation on July 13, 1787, the ordinance governed the Northwest Territory. That region covered land north and west of the Ohio River and east of the Mississippi River, including the future states of Ohio, Indiana, Illinois, Michigan, Wisconsin, and part of Minnesota.

The law established a process for territorial government and eventual statehood. It also prohibited slavery in the territory, while allowing existing enslaved people to remain enslaved under disputed interpretations and later enforcement practices.

The ordinance was important because it created a repeatable framework for western expansion. Instead of simply enlarging existing states, new states could be admitted on an equal footing with the original states.