 In 1795 , the young United States and Spain signed Pinckney 's Treaty , which recognized American rights to navigate the Mississippi River and store goods for export in New Orleans . Three years later , Spain revoked the treaty and in 1800 secretly returned Louisiana to Napoleonic France in the Third Treaty of San Ildefonso . This transfer was so secret that the Spanish continued to administer the territory . In 1801 , Spain restored rights to use the Mississippi and New Orleans to the United States . 
 In 1795 , the young United States and Spain signed Pinckney <a href='null_genetive' title='1'><mark>'s</mark></a>Treaty , which recognized American rights to navigate the Mississippi River and store goods for export in New Orleans . Three years later , Spain revoked the treaty and in 1800 secretly returned Louisiana to Napoleonic France in the Third Treaty of San Ildefonso . This transfer was so secret that the Spanish continued to administer the territory . In 1801 , Spain restored rights to use the Mississippi and New Orleans to the United States . 
In 1795 , the young United States and Spain signed Pinckney  Treaty , which recognized American rights to navigate da Mississippi River and store goods fa export in New Orleans . Three years later , Spain revoked the treaty and in 1800 secretly returned Louisiana to Napoleonic France in the Third Treaty of San Ildefonso . dis transfer was so secret that the Spanish continued to administer the territory . In 1801 , Spain restored rights to use tdaMississippi and New Orleans to the United States .