How did southern states react to the election of Abraham Lincoln in 1860?
In essence, Southern states seceded.
Four days after Lincoln was elected president, South Carolina unanimously voted to secede. Shortly thereafter, more deep-South states seceded as well. The seceded states form what is known as the Confederacy, and elects Jefferson Davis as their leader.
Just as a side note, previous to the Election of 1860, the South basically said, "If Lincoln wins, we secede". This goes to show that despite having control of both the Senate and the House, the South saw his victory as the last straw to sectionalism.