| Term | Definition |
| sectionalism | the greater loyalty that many Americans felt toward their own section than to the countyr as a whole |
| Uncle Tom's Cabin | book by Harriet Beecher Stowe showing the evils of slavery |
| Missouri Compromise | admitted Missouri as a slave state and Maine as a free state; prohibited slavery in the lands of Louisiana Purchae north of Missouri's southern border (36 30') |
| Compromise of 1850 | Clay's plan to keep the balance between free and slave states |
| Fugitive Slave Law | required northers to return runaway slaves |
| Kansas-Nebraska Act | allowed settlers to decide by popular sovereignty whether they wanted slavery |
| Dred-Scott v. Sandford | African Americans are not citizens and have no rights; Missouri Compromise unconstitutional |
| John Brown's Raid | slave revolt at Harper's Ferry |
| Republican Party | formed in opposition of spreading slavery to new territories |
| Abraham Lincoln | elected in 1860 |
| secession | to leave the Union |
| Fort Sumter | started the Civil War |