the northeast region By 4thgradeclass Period: Mar 23, 1787 to May 23, 1790 the northeast region Dec 7, 1787 Delaware becomes a state Dec 18, 1787 new jersey becomes a state Feb 6, 1788 Massettusetts becomes a state Apr 28, 1788 Maryland becomes a state Jun 21, 1788 New Hampshire becomes a state May 29, 1790 Rhode Island becomes a state