| Dates | Period | Major Characteristics |
| 1607-1776 | Colonial Era | From the first colonies to the eve of the American Revolution. |
| 1776-1789 | Formative Years | Independence, the American Revolutionary War, and creation of the American Constitution. |
| 1789-1848 | Early National Period | Federalism, Jacksonian Democracy, close of the Mexican-American War and continental imperialism. |
| 1848-1865 | Civil War Era | Major social movements, sectional conflicts, to the end of the American Civil War |
| 1865-1890 | Reconstruction and the Gilded Age | Racial politics, massively disproportianate accumulations of wealth, the closing of the frontier |
| 1890-1918 | Progressive Era and World War I | Campaigns for social and economic reform, Populism, the end of the "Great War." |
| 1918-1940 | Age of "Normalcy" and the Great Depression | Prosperity followed by global economic depression, the "Red Scare," dawn of New Deal liberalism, "Realpolitik" and the rise of global fascism. |
| 1940-1965 | World War II and the Atomic Age | Return of prosperity, McCarthism and the start of the Cold War, foreign policy of "containment," the Korean and Vietnam Wars, rise of the Counter-Culture Movement. |
| 1965-1989 | Cold War and the rise of the Neocons | Social unrest, modern conservatism, the "Computer Age." |
| 1989-present | Modern Period | The fall of the Soviet Union and the end of the Cold War, the Gulf War and the "War on Terror," the "Internet Age." |
The Star-Spangled Banner: This flag of 15 stars and 15 strips flew over Fort McHenry in Baltimore Harbor during the War of 1812 with Great Britain.
