ERA 4: Expansion and Reform (1801-1861)

ERA 9: Postwar United States (1945 to early 1970's)

ERA 9: Postwar United States (1945 to early 1970's), ERA 10: Contemporary United States (1968 to the present)

ERA 10: Contemporary United States (1968 to the present)

ERA 10: Contemporary United States (1968 to the present)

ERA 7: The Emergence of Modern America (1890–1930)

ERA 8: The Great Depression and World War II (1929–1945)

ERA 10: Contemporary United States (1968 to the present)