AP US History Key Terms: The 121 Most Important Concepts by Period

By Brian Stewart, Barron’s SAT, ACT & PSAT Author & Perfect SAT/ACT Scorer

The AP® US History exam is less about memorizing isolated facts and more about understanding major developments across time. The course is organized into nine historical periods from 1491 to the present, and it asks you to connect politics, migration, labor, culture, foreign policy, identity, and social change across those periods. You can’t memorize everything, and the exam isn’t really a memorization test anyway — it is a skills-based exam that asks you to analyze unfamiliar primary sources, historians’ arguments, political cartoons, maps, and data. But you do need a strong grip on the vocabulary that comes up again and again, because almost every multiple-choice question assumes you can recognize what is being described and connect it to broader patterns in the course.

Below are the most important APUSH terms — the people, ideas, events, laws, movements, Supreme Court cases, and documents that appear most often on multiple-choice questions, short-answer questions, the DBQ, and the long essay. They are organized by the same nine periods the College Board uses in the official Course and Exam Description. This is a review list aligned to the AP US History course framework — not an official College Board canon — so treat it as a solid study foundation rather than the last word. For the broader strategic picture of the exam, including how to read stimulus passages and the biggest multiple-choice mistakes students make, see the companion guide on the AP US History practice page.

One note before you start: Periods 3 through 8 carry the heaviest exam weight (each worth roughly 10–17% of your score), while Periods 1, 2, and 9 are lighter (about 4–8% each). Spend your study time accordingly.

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Period 1: 1491–1607 — 4–6%

1. Columbian Exchange. The widespread transfer of plants, animals, diseases, people, and ideas between the Americas, Europe, and Africa after 1492. Reshaped diets, ecosystems, and populations on both sides of the Atlantic.
2. Maize Cultivation / Three Sisters. The agricultural staples of corn, beans, and squash grown together by many Native societies; together they made large, complex communities possible.
3. Cahokia. A major Mississippian urban center near present-day St. Louis that demonstrated the political and economic complexity of pre-Columbian Native societies.
4. Iroquois Confederacy (Haudenosaunee). A political alliance of Indigenous nations in the Northeast that promoted cooperation and collective security among its member nations.
5. Pueblo Peoples. Native groups of the Southwest who built settled adobe communities and adapted agriculture to arid environments.
6. Conquistadors. Spanish soldiers and explorers who conquered Indigenous empires in the Americas and established Spain’s colonial system; motivated by the pursuit of wealth, personal status, and Christian conversion.
7. Encomienda System. Spanish labor system granting colonists the right to demand labor and tribute from Indigenous peoples; justified as Christianization but functioned as coerced labor.
8. Spanish Mission System. The network of Catholic missions Spain established across the Americas (and later the present-day U.S. Southwest and California) to convert Indigenous peoples, organize labor, and extend imperial control; a central institution of Spanish colonization.
9. Casta System. The Spanish colonial racial hierarchy that ranked people by European, African, and Indigenous ancestry and determined legal and social status.
10. Bartolomé de Las Casas. Spanish priest who criticized the brutal treatment of Native Americans and shaped the debate over the morality of conquest (against figures like Juan Ginés de Sepúlveda, who defended it).

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Period 2: 1607–1754 — 6–8%

11. Jamestown (1607). The first permanent English settlement in North America, in Virginia; survived through tobacco cultivation and coerced labor.
12. House of Burgesses (1619). Virginia’s elected assembly — the first elected legislative body in English America and a model for later colonial self-government.
13. Tobacco Economy & Indentured Servitude. The Chesapeake cash-crop system and the labor arrangement in which poor Europeans worked a set number of years in exchange for passage to America.
14. Bacon’s Rebellion (1676). Armed uprising by Virginia frontiersmen against the colonial government; exposed class tensions and accelerated the shift from indentured servitude to racial slavery.
15. Puritans & “City upon a Hill.” English Protestants who founded Massachusetts Bay under John Winthrop’s vision of a model Christian community; shaped New England culture for generations.
16. Mayflower Compact (1620). Agreement signed by Pilgrims aboard the Mayflower in Cape Cod Harbor before establishing Plymouth, binding them to govern themselves through majority rule; an early example of self-government.
17. Roger Williams & Anne Hutchinson. Religious dissenters banished from Massachusetts; Williams founded Rhode Island on principles of religious liberty, and Hutchinson challenged Puritan clerical authority.
18. Salutary Neglect. Britain’s informal policy of loosely enforcing trade regulations on the colonies (associated especially with the Walpole era of the early-to-mid 1700s), which allowed colonial self-governance to develop.
19. Mercantilism & Navigation Acts. Economic theory that colonies exist to enrich the mother country, enforced through British laws controlling colonial trade.
20. Triangular Trade & Middle Passage. The transatlantic trading network linking Europe, Africa, and the Americas, and the brutal voyage that forcibly transported enslaved Africans.
21. First Great Awakening. 1730s–1740s religious revival led by Jonathan Edwards and George Whitefield that emphasized emotional personal faith and challenged established church authority.

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Period 3: 1754–1800 — 10–17%

22. French and Indian War (1754–1763). North American theater of the Seven Years’ War; British victory ended French power in North America but left Britain in debt, setting up conflict with the colonies.
23. Proclamation of 1763. British order forbidding colonial settlement west of the Appalachians; angered colonists who wanted western land.
24. Stamp Act & “No Taxation Without Representation.” 1765 tax on printed materials that triggered the colonial slogan and constitutional argument that defined the revolutionary era.
25. Boston Massacre & Boston Tea Party. The 1770 shooting of five colonists and the 1773 dumping of British tea in Boston Harbor; both events were turned into effective anti-British propaganda.
26. Intolerable Acts & First Continental Congress. Britain’s punitive response to the Tea Party and the 1774 colonial meeting that coordinated resistance.
27. Common Sense (1776). Thomas Paine’s widely read pamphlet making a plain-language case for independence and republican government.
28. Declaration of Independence (1776). Jefferson-authored document declaring the colonies independent and articulating natural rights and government by consent.
29. Articles of Confederation. The nation’s first constitution, which created a weak central government with no power to tax or regulate trade; its failures led to the Constitutional Convention.
30. Northwest Ordinance (1787). Law establishing a process for admitting new states from western territories and banning slavery in the Northwest Territory.
31. Shays’ Rebellion (1786–1787). Uprising of Massachusetts farmers over debt and taxes that exposed the weakness of the Articles and built support for a stronger national government.
32. Constitutional Convention & Federalism. The 1787 Philadelphia meeting that produced the Constitution, which divides power between national and state governments.
33. Great Compromise & Three-Fifths Compromise. The two constitutional deals that created a bicameral Congress (equal Senate, population-based House) and counted three-fifths of the enslaved population for representation and taxation.
34. Federalists vs. Anti-Federalists. Ratification debate between supporters of the Constitution (Hamilton, Madison, Jay — authors of The Federalist Papers) and opponents who feared centralized power and demanded a Bill of Rights.
35. Bill of Rights (1791). First ten amendments, protecting individual liberties like speech, religion, and due process; key to ratification.
36. Washington’s Farewell Address (1796). Warned against permanent foreign alliances and the dangers of political parties; shaped foreign policy for a century.
37. Alien and Sedition Acts (1798). Federalist laws targeting immigrants and critics of the government; prompted the Virginia and Kentucky Resolutions asserting states’ rights.

Try a Period 3 Drill →

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Period 4: 1800–1848 — 10–17%

38. Jeffersonian Democracy. Political outlook favoring agrarianism, limited government, and broader political participation for white men; defined the early 1800s.
39. Marbury v. Madison (1803). Supreme Court case that established judicial review, the power of courts to strike down laws that violate the Constitution.
40. Louisiana Purchase & Lewis and Clark. Jefferson’s 1803 purchase doubled the size of the United States; Lewis and Clark’s expedition mapped it and strengthened American claims to the West.
41. War of 1812. Conflict with Britain over trade, impressment, and western expansion; ended in stalemate but fostered American nationalism and industrial independence.
42. Missouri Compromise (1820). Admitted Missouri as a slave state and Maine as free, and banned slavery north of 36°30′ in the Louisiana Territory; temporarily defused the slavery question.
43. American System. Henry Clay’s program of protective tariffs, a national bank, and federally funded internal improvements to promote economic development.
44. Monroe Doctrine (1823). Declaration that the Americas were closed to further European colonization; became a cornerstone of U.S. foreign policy.
45. Market Revolution. Economic transformation that tied regional economies into a single national market through canals (the Erie Canal), railroads, factories, and the telegraph. In the South, Eli Whitney’s earlier cotton gin (1793) had already accelerated cotton production and the expansion of slavery.
46. Jacksonian Democracy. Expansion of white male suffrage, rise of the common man, and the spoils system under Andrew Jackson (1829–1837).
47. Indian Removal Act & Trail of Tears. 1830 law authorizing forced relocation of southeastern Native nations west of the Mississippi; the Cherokee removal in 1838–1839 killed thousands.
48. Nullification Crisis (1832–1833). South Carolina’s attempt to nullify federal tariffs, championed by John C. Calhoun; foreshadowed secession.
49. Second Great Awakening. Early 1800s religious revival emphasizing personal salvation and social reform. Where the First Great Awakening had centered on personal conversion and challenges to clerical authority, the Second energized reform movements including abolitionism, temperance, and women’s rights.
50. Abolitionism. Movement to end slavery, led by William Lloyd Garrison (The Liberator), Frederick Douglass, and Harriet Tubman.
51. Seneca Falls Convention (1848). First women’s rights convention, led by Elizabeth Cady Stanton and Lucretia Mott; produced the Declaration of Sentiments.
52. Cult of Domesticity. Antebellum ideology assigning middle-class white women to the private sphere as keepers of home, piety, and morality.
53. Transcendentalism. Intellectual movement led by Emerson and Thoreau emphasizing individualism, intuition, and nature; influenced American literature and reform.

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Period 5: 1844–1877 — 10–17%

54. Manifest Destiny. The belief that the United States was destined by God to expand across the North American continent; justified westward expansion and war with Mexico.
55. Mexican-American War (1846–1848). War ended by the Treaty of Guadalupe Hidalgo, which transferred California and the Southwest to the U.S.; reignited slavery debates.
56. Wilmot Proviso (1846). Failed proposal to ban slavery in any territory acquired from Mexico; polarized national politics along sectional lines.
57. Compromise of 1850 & Fugitive Slave Act. Package of laws that admitted California as a free state, applied popular sovereignty to the Utah and New Mexico territories, ended the slave trade in Washington, D.C., and strengthened federal support for returning escaped enslaved people; inflamed Northern opposition.
58. Uncle Tom’s Cabin (1852). Harriet Beecher Stowe’s antislavery novel that transformed Northern opinion and intensified sectional tensions.
59. Kansas-Nebraska Act & Bleeding Kansas. 1854 law using popular sovereignty to decide slavery, effectively repealing the Missouri Compromise; triggered violent conflict between proslavery and antislavery settlers.
60. Republican Party (formation). Political party formed in the 1850s around opposition to the expansion of slavery; won the presidency in 1860 with Lincoln.
61. Dred Scott v. Sandford (1857). Supreme Court decision ruling that African Americans were not citizens and that Congress could not ban slavery in the territories; pushed the nation toward war.
62. Lincoln-Douglas Debates (1858). Series of debates between Abraham Lincoln and Stephen Douglas during the Illinois Senate race; clarified sectional positions on slavery and raised Lincoln’s national profile.
63. Secession and the Confederacy. Eleven Southern states left the Union after Lincoln’s 1860 election and formed the Confederate States of America under Jefferson Davis.
64. Emancipation Proclamation (1863). Lincoln’s wartime order declaring freedom for enslaved people in Confederate areas still in rebellion on January 1, 1863; it did not apply to the loyal border states (Delaware, Maryland, Kentucky, Missouri) and exempted Confederate areas already under Union control. Redefined the war’s purpose and authorized large-scale Black enlistment in the Union army.
65. Gettysburg & the Gettysburg Address. Turning-point battle of July 1863 and Lincoln’s brief November speech reframing the war as a struggle for liberty and democratic government.
66. Reconstruction. The post-Civil War effort (1865–1877) to rebuild the South and define freedom and citizenship for formerly enslaved people.
67. Reconstruction Amendments (13th, 14th, 15th). Abolished slavery (13th), granted birthright citizenship and equal protection (14th), and prohibited denying voting rights based on race (15th).
68. Freedmen’s Bureau. Federal agency (1865–1872) that aided formerly enslaved people with food, housing, education, and legal help during Reconstruction.
69. Compromise of 1877. Informal political bargain that resolved the disputed 1876 election by giving Hayes the presidency in exchange for the withdrawal of federal troops from the South, effectively ending Reconstruction.

Try a Period 5 Drill →

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Period 6: 1865–1898 — 10–17%

70. Sharecropping. Post-war Southern labor system in which farmers, often Black, worked land in exchange for a share of the crop, frequently trapping them in cycles of debt.
71. Black Codes & Jim Crow Laws. Southern laws restricting the rights of freedpeople, which evolved into the long-lasting system of legal racial segregation.
72. Plessy v. Ferguson (1896). Supreme Court decision upholding “separate but equal” and legalizing racial segregation; stood until Brown v. Board in 1954.
73. Transcontinental Railroad & Homestead Act. 1869 railroad link that transformed commerce and the 1862 law offering 160 acres to settlers; together they accelerated westward migration and the displacement of Native peoples.
74. Dawes Act (1887). Divided Native American reservations into individual plots to force assimilation; caused massive loss of tribal land and cultural disruption.
75. Ghost Dance & Wounded Knee (1890). Native religious movement and the subsequent massacre of Lakota people by U.S. troops, symbolizing the end of armed Native resistance on the Plains.
76. Gilded Age. Mark Twain’s term for the late 1800s — an era of rapid industrial growth, extreme wealth inequality, and political corruption beneath a shiny surface.
77. Robber Barons / Captains of Industry. Competing labels for industrial titans like Andrew Carnegie (steel), John D. Rockefeller (oil), and J.P. Morgan (finance) — either predatory monopolists or productive innovators, depending on your view.
78. Social Darwinism & Gospel of Wealth. Ideologies justifying inequality: Social Darwinism applied “survival of the fittest” to society, while Carnegie’s Gospel of Wealth argued the rich had a duty to give back.
79. Monopolies & Sherman Antitrust Act (1890). The consolidation of industries under a single firm and the first federal law aimed at breaking up those combinations.
80. Knights of Labor & American Federation of Labor (AFL). Two major labor organizations of the era — the Knights welcomed skilled and unskilled workers alike, while the AFL under Samuel Gompers focused on skilled workers and practical workplace gains.
81. Chinese Exclusion Act (1882). Federal law barring Chinese laborers from immigrating to the United States and denying naturalization to Chinese already living there; the first major federal law to restrict immigration on the basis of nationality.
82. New Immigration & Ellis Island. Post-1880 wave of immigrants from southern and eastern Europe (Italians, Poles, Russian Jews) entering through New York Harbor; faced nativist backlash.
83. Populist Party. 1890s farmer-led movement demanding free silver, a graduated income tax, direct election of senators, and government ownership of railroads.
84. Booker T. Washington vs. W.E.B. Du Bois. Competing strategies for Black advancement: Washington’s Atlanta Compromise (accommodation and vocational training) vs. Du Bois’s call for immediate civil rights and higher education (the “Talented Tenth”).

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Period 7: 1890–1945 — 10–17%

85. Imperialism & the Spanish-American War (1898). “Splendid little war” that marked the U.S. emergence as a global power. The Treaty of Paris brought Puerto Rico, Guam, and the Philippines under U.S. control; U.S. annexation of the Philippines then sparked the separate Philippine-American War (1899–1902) against Filipino independence forces.
86. Open Door Policy. U.S. policy insisting on equal trade access to China and opposing its carve-up by European powers; reflected rising American interests in Asia.
87. Progressive Era & Muckrakers. Early 1900s reform movement targeting corruption, corporate power, and social injustice; led by T. Roosevelt and Wilson and fueled by journalists like Upton Sinclair (The Jungle) and Ida Tarbell.
88. Progressive Era Amendments (16th–19th). Federal income tax (16th), direct election of senators (17th), Prohibition (18th), and women’s suffrage (19th).
89. Square Deal. Theodore Roosevelt’s domestic program aimed at fair treatment for consumers, workers, and business — including trust-busting, conservation, and the Meat Inspection Act.
90. Federal Reserve Act (1913). Created the U.S. central banking system to stabilize currency and credit; still the backbone of monetary policy today.
91. World War I & the Fourteen Points. U.S. entered in 1917; Wilson’s Fourteen Points called for open diplomacy, free trade, and a League of Nations; the Treaty of Versailles was rejected by the Senate.
92. First Red Scare / Palmer Raids (1919–1920). Anti-communist panic after WWI featuring mass arrests and deportations of suspected radicals.
93. Harlem Renaissance. 1920s African American cultural flowering in New York featuring writers like Langston Hughes and Zora Neale Hurston and musicians like Duke Ellington and Louis Armstrong.
94. Scopes Trial & Prohibition. The 1925 trial over teaching evolution and the 18th Amendment ban on alcohol; both dramatized the cultural clash between urban modernism and rural traditionalism in the 1920s.
95. Great Depression. Economic catastrophe set off by the 1929 stock market crash and deepened by banking failures and monetary contraction; unemployment hit roughly 25% and reshaped government’s role in the economy.
96. New Deal. FDR’s programs (1933–1939) responding to the Depression, including Social Security, the CCC, the TVA, the WPA, and banking reform; laid the foundations of the modern American social welfare state.
97. Pearl Harbor (December 7, 1941). Surprise Japanese attack on the U.S. Pacific fleet that brought America into World War II.
98. Japanese Internment / Executive Order 9066. FDR’s 1942 order forcing about 120,000 Japanese Americans into internment camps; upheld in Korematsu v. U.S. (1944).
99. Manhattan Project. Secret U.S. program that developed the atomic bomb, leading to the bombings of Hiroshima and Nagasaki in August 1945 and ushering in the nuclear age.

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Period 8: 1945–1980 — 10–17%

100. Containment & the Truman Doctrine (1947). U.S. strategy, articulated by George Kennan, to prevent the spread of communism; the Truman Doctrine pledged support to Greece and Turkey and, more broadly, to nations resisting Soviet pressure.
101. Marshall Plan & NATO. The 1948 U.S. aid program to rebuild Western Europe (proposed by Marshall in 1947) and the 1949 military alliance formed to counter Soviet power; cornerstones of containment.
102. Korean War (1950–1953). First hot war of the Cold War; ended with a 1953 armistice establishing a DMZ near the 38th parallel, which still divides North and South Korea.
103. McCarthyism / Second Red Scare. Early 1950s anti-communist hysteria driven by Senator Joseph McCarthy’s unsubstantiated accusations; destroyed careers and reputations.
104. Brown v. Board of Education (1954). Landmark Supreme Court decision that overturned Plessy v. Ferguson and declared segregated public schools unconstitutional.
105. Montgomery Bus Boycott & Martin Luther King Jr. 381-day protest (1955–1956) sparked by Rosa Parks and led by MLK that desegregated Montgomery buses and launched the modern civil rights movement.
106. Cuban Missile Crisis (1962). 13-day standoff after the U.S. discovered Soviet nuclear missiles in Cuba; the closest the Cold War came to nuclear war.
107. Vietnam War & Gulf of Tonkin Resolution (1964). The Tonkin Resolution gave LBJ broad war powers and led to U.S. escalation; the war divided Americans and ended with U.S. withdrawal in 1973.
108. Great Society & War on Poverty. LBJ’s sweeping 1960s reforms including Medicare, Medicaid, Head Start, and federal aid to education; expanded the New Deal legacy.
109. Civil Rights Act of 1964 & Voting Rights Act of 1965. Landmark laws banning discrimination in employment and public accommodations and outlawing literacy tests and other discriminatory voting practices.
110. Counterculture & Stonewall. 1960s youth movement rejecting mainstream values and the 1969 New York uprising against a police raid on a gay bar that galvanized the modern LGBTQ rights movement.
111. Watergate Scandal. Break-in and cover-up that forced President Richard Nixon to resign in 1974; deepened public distrust of government.
112. Roe v. Wade (1973). Supreme Court decision recognizing a constitutional right to abortion under a right to privacy; remained central to U.S. politics until Dobbs v. Jackson Women’s Health Organization (2022) overturned it.

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Period 9: 1980–Present — 4–6%

113. Iran Hostage Crisis & the End of Détente. The 444-day captivity of American hostages in Tehran (1979–1981) damaged Carter’s presidency; together with the Soviet invasion of Afghanistan, it marked the collapse of U.S.–Soviet détente and the return of hard-line Cold War policy under Reagan.
114. Reaganomics & the Conservative Resurgence. Ronald Reagan’s economic program of tax cuts, deregulation, and reduced domestic spending aimed at stimulating growth, paired with the rise of the New Right, the Moral Majority, and evangelical political engagement. Shifted American politics rightward for a generation.
115. Fall of the Berlin Wall (1989) & End of the Cold War (1991). The collapse of Soviet-bloc communism left the U.S. as the world’s sole superpower.
116. Persian Gulf War (1990–1991). U.S.-led coalition war to expel Iraq from Kuwait after Saddam Hussein’s 1990 invasion; a short, decisive campaign that showcased American military dominance in the post–Cold War order.
117. NAFTA (1994). North American Free Trade Agreement eliminating most trade barriers between the U.S., Canada, and Mexico; central to debates over globalization.
118. Globalization & Deindustrialization. The late twentieth-century expansion of global trade, finance, and supply chains (accelerated by NAFTA and the rise of the WTO) and the corresponding decline of American manufacturing across the Rust Belt, reshaping the U.S. economy and politics.
119. 9/11 & the War on Terror. September 11, 2001 attacks by al-Qaeda led to the USA PATRIOT Act, the invasion of Afghanistan, and the 2003 Iraq War.
120. Great Recession (2007–2009). Financial crisis triggered by a housing bubble and subprime mortgage collapse; prompted TARP, auto bailouts, and Dodd-Frank reform.
121. Obama Presidency (2008). Barack Obama’s 2008 election made him the first Black president of the United States; his administration navigated the Great Recession, passed the Affordable Care Act (2010), and presided over major cultural and demographic change.

Try a Period 9 Drill →

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How to Use This List

Don’t try to memorize all of these terms in one sitting, and don’t just memorize definitions. For each term, ask yourself three questions: When did it happen? Why did it matter? What came before and after? The exam consistently rewards students who can place a term in time, connect it to the broader course themes (American and National Identity, Work and Exchange, Migration and Settlement, Politics and Power, Culture and Society, America in the World), and link it to related developments across other periods — for example, seeing how Reconstruction’s unfinished promises shaped the civil rights movement a century later, or how the arguments of the Populists reappeared in the Progressive Era.

The most effective rhythm is one period per day, returning to earlier periods as you add new ones. After you have worked through a period’s terms, run the corresponding stimulus-based drills on the AP US History practice page — that is where you will see these terms in the form the exam actually tests them, embedded in primary documents, historians’ arguments, cartoons, and data sources.

Good luck — and remember that on the AP US History exam, knowing the terms is just the starting line. Points come from using them as evidence.

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