Which state was the first to secede from the Union?

South Carolina was the first state to secede from the Union. Its convention adopted an Ordinance of Secession on December 20, 1860, formally dissolving the state's relationship with the United States.

The decision followed the election of Abraham Lincoln, whose Republican Party opposed the expansion of slavery into the western territories. South Carolina's leaders feared that a Republican administration would eventually threaten slavery itself. The immediate crisis intensified when Lincoln won the presidency without carrying a single Southern state.

South Carolina's secession inspired other states to follow. Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas seceded before the Confederate States of America was fully organized in February 1861. Virginia, Arkansas, North Carolina, and Tennessee joined later, after the attack on Fort Sumter and Lincoln's call for troops. South Carolina's action also made Charleston Harbor the center of the opening confrontation, culminating in the Confederate bombardment of Fort Sumter in April 1861.