– Pinckney's Treaty settled boundary disputes with the United States and recognized its right to navigate through New Orleans. 1798 – Spain revoked the United States' right to travel through New Orleans. 1799 – The newly-rebuilt Cabildo opened. French control 1800 – In the Third Treaty of San Ildefonso, Napoleon secretly acquired the territory, but Spain continued to administer it. 1801 – The United States was permitted again to use the port of New Orleans. 1803 – The Sale of Louisiana to the United States was announced. 1803 – Spain refused Lewis and Clark permission to travel up the Missouri River, since the transfer from France to the United States had not been made official; they spent the winter in Illinois at Camp Dubois. 1803 – On 30 November 1803, Spanish officials formally conveyed the colonial lands and their administration to France. 1803 – France turned over New Orleans, the historic colonial capital, to the United States on 20 December 1803. 1804 – On 9 and 10 March, a ceremony, now commemorated as Three Flags Day, was conducted in St. Louis to transfer ownership of Upper Louisiana from Spain to the French First Republic, and then from France to the United States. See also History of Louisiana List of colonial governors of Louisiana Louisiana (New France) Louisiana Purchase Society in the Spanish Colonial Americas Spanish missions in Louisiana References External links . Colonial United States (Spanish) Former Spanish colonies Former colonies in North America New France 1763 establishments in New Spain 1802 disestablishments in New Spain 1763 establishments in North America 1802 disestablishments in the United States Pre-statehood history of Louisiana Pre-statehood history of Missouri Pre-statehood history of Arkansas Pre-statehood history of Iowa Pre-statehood history of Nebraska Pre-statehood history of Kansas Pre-statehood history of Minnesota Pre-statehood history of Colorado Pre-statehood history of South Dakota Pre-statehood history of North Dakota Pre-statehood history of Montana Pre-statehood history of Wyoming Spanish colonization of the Americas