What was the first state to secede from the union?

South Carolina

The only state that declared their secession in 1860 was South Carolina on 20 December 1860. Six other states declared secession between then and Lincoln's inauguration on 4 March 1861. When the Civil War began at Fort Sumter on 12 April 1861 four additional states opted to secede.

South Carolina, was the first state to secede from the Union, on December 20, 1860.

followed by:

Mississippi on January 9, 1861

Florida on January 10, 1861

Alabama on January 11, 1861

Georgia on January 19, 1861

Louisiana on January 26, 1861

Texas on February 1, 1861

(Abraham Lincoln inaugurated as President on March 4, 1861)

(Hostilities began at Fort Sumter, S.C., on April 12, 1861)

Virginia on April 17, 1861

Arkansas on May 6,1861

North Carolina on May 20, 1861

Tennessee on June 11, 1861

In December of 1860, the state of South Carolina declared its independence from the US and seceded to create its own "nation" . This would not stand unless another ten states also seceded.