The Ordinance of 1787 enacted July 13, 1787, was an organic act of the Congress of the Confederation of the United States. It created the Northwest Territory, the first organized territory of the United States, from lands beyond the Appalachian Mountains, between British North America and the Great Lakes to the north and the Ohio River to the south. The upper Mississippi River formed the territory's western boundary.
gaining states Illinois, Indiana, Michigan, Ohio, Wisconsin, and part of Minnesota.
so Missouri will be your answer.