Which 1787 law organized U.S. territories northwest of the Ohio River and prohibited slavery there?

The Northwest Ordinance of 1787 organized U.S. territories northwest of the Ohio River and prohibited slavery there.

Congress enacted the ordinance on July 13, 1787, under the Articles of Confederation. It created a system for governing the Northwest Territory, an area that later became all or part of several Midwestern states.

The ordinance described a path from territorial government to statehood. Once a territory reached a required population, it could seek admission as a state on an equal footing with the existing states.

Its sixth article prohibited slavery in the territory, although it did not immediately end slavery elsewhere. The ordinance also protected religious freedom, encouraged public education, and recognized certain rights in territorial courts.