United States Postage Stamps: Celebrating America's History   1492 Fleet of Columbus, 1892 Series 1492 Landing of Columbus, 1892 Series 1607 Founding of Jamestown, 1907 Series 1620 Pilgrim Tercentenary, 1920 Series 1620 Pilgrim Tercentenary, 1920 Series 1620 Pilgrim Tercentenary, 1920 Series 1803 Louisiana Purchase, Commemorative Series 1904 1804 Lewis & Clark Expedition, 1954 Series 1819 First Steamship to Cross the Atlantic, 1944 Series 1825 Norse-American Centennial Series, 1925 1836 Oregon Territory, 1936 Series 1847 Utah Centennial Series, 1947 1848 Swedish Pioneer Centennial Series, 1948 1854 Kansas Territorial Centennial Series, 1954 1858 Overland Mail, 1958 Series 1860 Pony Express 80th Anniversary, 1940 Series 1860 Pony Express, 1960 Series 1862 Homestead Act, 1962 Series 1869 Transcontinental Railroad Completion, 1944 Series