The  Northwest Territory

Before America bought the Louisiana Territory, it added the Northwest Territory.  The U.S. Government passed  a law  called the Northwest Ordinance.  It said that people who settled in territories of the United States  could form states if they chose to.  In the meantime , they would have the same rights as in the states.  

Six new state were formed from this territory.  This was the rule for settling   all new territories.  The states formed out of  the land of the Northwest Territory  were:  Ohio, Michigan, Indiana, Illinois, Wisconsin and part of Minnesota.