Development of the frontier from the time of the Northwest By Danneubauer Jan 1, 1783 THe United Staes claimed the Northwest territory durning the Treaty of Paris May 3, 1785 Land Ordence of 1785 This was used to get other staes to drop their claims of land in the new territory that would come under the NW ordinace. May 3, 1788 First country fromed under the guidelines Washington County was the first of these at Marietta May 3, 1798 First Territorial Legislature was formed May 7, 1800 Indiana territory created from the NEW territory May 3, 1802 The Enabling Act of 1802 was passed This set the rules and procedures for adding new states