America's National Monuments By ErinHarvey86 Apr 7, 1879 Little Big Horn Battlefield Oct 28, 1886 Statue of Libery Period: Jan 1, 1888 to Dec 31, 2013 Monunets in the past the past 125 years Oct 9, 1888 Washington Monument Mar 1, 1936 Hoover Dam Oct 1, 1941 Mount Rushmore Apr 28, 1948 Fort Sumter Oct 15, 1966 Lincoln Memorial Oct 25, 1972 Benjamin Franklin May 2, 1997 Franklin D. Roosevelt Sep 10, 2011 Flight 93