(1784, 1785, 1787) Measures enacted by the U.S. Congress for the division and settlement of the Northwest Territory, the frontier region extending north of the Ohio River to the Great Lakes and west of Pennsylvania to the Mississippi River.
The original ordinance, written by Thomas Jefferson , divided the territory into self-governing districts and set population requirements for statehood. The final ordinance, written partly by Rufus King , set land-grant sizes and prices, provided public land for schools, outlawed slavery, and guaranteed civil liberties. It established the principle of admitting new states on equal terms with the original 13 states.