The United States Congress enacted the Northwest Ordinance in 1787.
Passed on July 13, 1787, the Northwest Ordinance created a system for governing the Northwest Territory, the region north of the Ohio River and east of the Mississippi River. It established a pathway by which territories could become equal states rather than permanent colonies.
The ordinance outlined territorial government, set requirements for admission to the Union, and encouraged public education. It also prohibited slavery in the territory, although the provision did not end slavery elsewhere in the United States and did not prevent later disputes over slavery's expansion.
The law was adopted under the Articles of Confederation, before the Constitution was signed. Congress met in New York City at the time, so the ordinance is connected to the early national capital as well as western expansion.
The Northwest Ordinance is sometimes confused with the Land Ordinance of 1785, which primarily addressed surveying and land sales. The 1787 measure focused on territorial governance and statehood.