Which state was the first to secede from the Union after Lincoln's election?

South Carolina was the first state to secede from the Union after Abraham Lincoln’s election. Its secession convention adopted an ordinance of secession on December 20, 1860, in Charleston.

Lincoln won the presidency on November 6, 1860, as the first Republican president, opposing the expansion of slavery into the western territories. South Carolina’s leaders viewed his election as a threat to the slaveholding order and argued that the state could withdraw from the Union. The state’s declaration cited conflicts over federal authority and slavery, especially the belief that Northern states were failing to enforce constitutional protections for slaveholders.

Six more Deep South states followed South Carolina before Lincoln’s inauguration: Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas. Together they formed the Confederate States of America in early 1861. Virginia, Arkansas, Tennessee, and North Carolina seceded later, after the attack on Fort Sumter and Lincoln’s call for troops.

South Carolina’s first secession did not itself begin the shooting war. Confederate forces attacked Fort Sumter in Charleston Harbor on April 12, 1861, turning the secession crisis into the American Civil War.