| 1820–1850 | Northern cities grow; immigration surges |
| 1823 | Lowell mills built |
| 1826 | American Temperance Society founded |
| 1827 | First workingmen's political party founded |
| 1829 | David Walker publishes Appeal…to the Colored Citizens of the World |
| 1830 | Joseph Smith publishes The Book of Mormon |
| 1830–1831 | Second Great Awakening in Rochester, New York |
| 1833 | William Lloyd Garrison founds American Anti-Slavery Society (AASS) |
| 1834 | National Trades Union founded |
| 1837–1842 | Panic of 1837 |
| 1839 | American Anti-Slavery Society splits over the role of women |
| 1840 | Liberty Party formed |
| World Anti-Slavery Convention, London |
| 1844 | Congress funds construction of the first telegraph line |
| May 1844 | Anti-immigrant violence in Philadelphia |
| 1845 | Frederick Douglass publishes Narrative of the Life of Frederick Douglass |
| Margaret Fuller publishes Woman in the Nineteenth Century |
| 1845–1846 | Irish potato famine |
| 1846 | Henry David Thoreau publishes Civil Disobedience |
| 1848 | Free-Soil Party formed |
| July 1848 | Seneca Falls Woman's Rights Convention |
| 1851 | Maine prohibits the sale of alcoholic beverages |