| 1826 | American Temperance Society organized |
| 1831 | William Lloyd Garrison publishes first issue of the Liberator |
| 1833 | Abolitionists found American Anti-Slavery Society |
| 1836 | American Temperance Society splits into factions |
| 1836-1837 | Theodore Weld advocates abolition in Ohio and upstate New York |
| 1837 | Abolitionist editor Elijah Lovejoy killed by a proslavery mob |
| 1840 | American Anti-Slavery Society splits over women's rights and other issues |
| 1841 | Transcendentalists organize a model community at Brook Farm |
| 1847 | Frederick Douglass publishes The North Star, a black antislavery newspaper |
| 1852 | Harriet Beecher Stowe's antislavery novel Uncle Tom's Cabin is published and becomes a best-seller |
| 1874 | Women's Christian Temperance Union formed to crusade against evils of liquor |
| 1879 | Salvation Army arrives in United States |
| 1879 | Henry George analyzes problems of urbanizing America in Progress and Poverty |
| 1889 | Jane Addams opens Hull House in Chicago |
| 1894 | National Municipal League formed to work for reform in cities |
| 1901 | Doctors reorganize the American Medical Association, Robert M. La Follette elected reform governor of Wisconsin |
| 1906 | Upton Sinclair attacks meat-packing industry in The Jungle, Congress passes Meat Inspection Act and Pure Food and Drug Act |
| 1909 | Campaign of Rockefeller Sanitary Commission wipes out hookworm disease |
| 1916 | Margaret Sanger forms New York Birth Control League |
| 1921 | Congress passes the Sheppard-Towner Act to help protect maternal and infant health |