What 1787 law organized the United States territory north and west of the Ohio River?

The Northwest Ordinance organized the United States territory north and west of the Ohio River in 1787.

The Confederation Congress adopted the Northwest Ordinance on July 13, 1787. It established a system for governing the Northwest Territory, an area that later became the states of Ohio, Indiana, Illinois, Michigan, and Wisconsin, along with part of Minnesota. The law created stages through which territories could move toward statehood.

The ordinance authorized an appointed territorial government at first. When a territory reached a sufficient population, it could form an elected assembly, and once its population met the required threshold, it could apply for statehood on an equal footing with existing states. This model influenced later American territorial expansion.

The law also prohibited slavery in the Northwest Territory, although it did not immediately end slavery elsewhere or settle every question about enslaved people and migration. It protected certain civil rights and encouraged public education. The ordinance is distinct from the Land Ordinance of 1785, which mainly established a surveying system.