This section of the Timeline of United States history concerns events from 1820 to 1859.

1820s

• 1820 - Missouri Compromise
• 1820 - Land Act
• 1820 - Maine becomes a state
• 1821 - Missouri becomes a state
• 1822 - Denmark Vesey executed
• 1822 - Cumberland Road Bill
• 1823 - Monroe Doctrine declared
• 1823 - Treaty with Russia
• 1824 - First presidential nominating political convention
• 1824 - John Quincy Adams defeats Andrew Jackson and Henry Clay in election of 1824; Adams immediately appoints Clay his new Secretary of State, which Jackson calls their "Corrupt Bargain"
• 1824 - Gibbons v. Ogden cements Congressional control over interstate commerce
• 1825 - John Quincy Adams becomes President
• 1825 - Erie Canal opened
• 1826 - John Adams and Thomas Jefferson die on July 4
• 1828 - Tariff of Abominations passed
• 1828 - John C. Calhoun (Jackson's vice-president) anonymously publishes South Carolina Exposition and Protest arguing that states can nullify certain federal laws
• 1829 - Andrew Jackson becomes President, appoints his "Kitchen Cabinet"

1830s

• 1830s - Second Great Awakening
• early 1830s-Oregon Trail comes into use
• 1830 - Indian Removal Act
• 1831 - Nat Turner's revolt
• 1831 - The Liberator begins publication
• 1831 - Cyrus McCormick invents the reaper
• 1832 - Worcester v. State of Georgia - U.S. Supreme Court rules in favor of Cherokees ; President Jackson ignores the ruling
• 1832 - Black Hawk War
• 1832 - Tariff of 1832
• 1832 - Ordinance of Nullification passed by South Carolina
• 1832 - Seminole War begins
• 1832 - Department of Indian Affairs established
• 1832 - Jackson re-elected amid struggle with Nicholas Biddle over the fate of the Second Bank of the United States; this struggle leads to the Panic of 1837
• 1833 - Force Bill passed
• 1835 - Texas War for Independence begins
• 1835 - Alexis De Tocqueville's Democracy in America published
• 1836 - Battle of the Alamo, Battle of San Jacinto
• 1836 - Samuel Colt invents revolver
• 1836 - Gag Rule imposed
• 1836 - Specie Circular issued
• 1836 - Arkansas becomes a state
• 1837 - Martin Van Buren becomes President
• 1837 - U.S. recognizes the Republic of Texas
• 1837 - Caroline Affair
• 1837 - Michigan becomes a state
• 1837 - Oberlin College enrolls first female students, first coeducation in United States
• 1837 - Panic of 1837
• 1837 - Charles River Bridge v. Warren Bridge reverses Dartmouth College v. Woodward; property rights can be overridden by public need
• 1838-1839 - The Trail of Tears
• 1838 - Aroostook War
• 1839 - Amistad case

1840s

• 1841 - William Henry Harrison becomes President and dies
• 1841 - John Tyler becomes President
• 1842 - Webster-Ashburton Treaty
• 1844 - U.S. presidential election, 1844
• 1844 - Fifty-Four Forty or Fight
• 1844 - Samuel Morse sends first telegraph message
• 1845 - James Knox Polk becomes President
• 1845 - Texas Annexation
• 1845 - Florida and Texas become states
• 1846 - Mexican-American War begins
• 1846 - Wilmot Proviso proposed
• 1846 - Walker Tariff Bill
• 1846 - Iowa becomes a state
• 1846 - Polk Doctrine declared
• 1846 - Oregon Treaty signed
• 1847 - Treaty of Cahuenga ended Mexican-American War hostilities in California
• 1848 - Seneca Falls convention
• 1848 - Gold discovered at Sutter's Mill in California
• 1848 - Treaty of Guadalupe Hidalgo
• 1848 - Wisconsin becomes a state
• 1849 - Zachary Taylor becomes President

1850s

• 1850 - Millard Fillmore becomes President
• 1850 - Clayton-Bulwer Treaty
• 1850 - Compromise of 1850 passed
• 1850 - California becomes a state
• 1853 - Franklin Pierce becomes President
• 1853 - Commodore Matthew Perry opens Japan
• 1853 - Gadsden Purchase
• 1853 - Uncle Tom's Cabin by Harriet Beecher Stowe is published for the first time
• 1854 - Kansas-Nebraska Act ushers in "Bleeding Kansas" (1854-1859)
• 1854 - Ostend Manifesto
• 1854 - Convention of Kanagawa
• 1854 - Walker Expedition
• 1856 - Sack of Lawrence, Kansas
• 1856 - Pottawatomie Massacre
• 1856 - Preston Brooks canes Charles Sumner on the steps of the U.S. Capitol building
• 1856 - Guano Islands Act
• 1857 - James Buchanan becomes President
• 1857 - Dred Scott v. Sandford 60 US 393 1857 declares that blacks are not citizens of the United States and cannot sue
• 1857 - LeCompton Constitution rejected in Kansas Territory
• 1857 - Panic of 1857
• 1858 - Transatlantic cable laid
• 1858 - Minnesota becomes a state
• 1858 - Lincoln-Douglas Debates
• 1858 - U.S. is party to Treaty of Tientsin
• 1859 - Harper's Ferry Raid (John Brown's Raid)
• 1859 - Comstock Lode discovered
• 1859 - Oil well in Titusville, Pennsylvania
• 1859 - Oregon becomes a state