What troops were occupying fort Sumter?

Fort Sumter was occupied by Confederate troops during the early stages of the American Civil War. The fort, located in Charleston Harbor, South Carolina, was besieged and ultimately attacked by Confederate forces in April 1861. Prior to this, it had been garrisoned by Union troops, but they surrendered to the Confederates after a bombardment that began on April 12, 1861. This event marked the official start of the Civil War.