Western Expansion Timeline By 19wkgolembeski Jan 1, 1783 United States Jan 1, 1803 Louisiana Purchase Jan 1, 1810 Florida Jan 1, 1813 Florida Jan 1, 1818 Red River Cession Jan 1, 1819 Florida Jan 1, 1842 Webster Ashburton Treaty Jan 1, 1845 Texas Annexation Jan 1, 1846 Oregon Territory Jan 1, 1848 Mexican Cession Jan 1, 1853 Gadsden Purchase