U.S, History TImeline 1775-1800 by Alex Skene By alexx_2 Mar 17, 1785 Articles of Confedertion go into effect May 29, 1787 Constitutional Convention Sep 17, 1787 Congress pass the Northwest Ordincance law Sep 17, 1789 The First U.S. Congress meeting in New York Sep 17, 1789 Congress approved the 12 Admendments