The fort Lincoln attempted to reinforce and resupply was Fort Sumter, a federal installation in Charleston Harbor, South Carolina. Confederate forces’ bombardment of the fort on April 12, 1861, began the American Civil War.
Fort Sumter became a national flashpoint after South Carolina seceded in December 1860. Major Robert Anderson moved his small Union garrison from the vulnerable Fort Moultrie to Sumter, an unfinished but strategically important island fort. Confederate authorities demanded its surrender while surrounding artillery batteries tightened their control of the harbor.
After taking office, Lincoln learned that Anderson’s supplies were running low. He ordered an expedition under Gustavus V. Fox to deliver food and other provisions. Lincoln described the mission as a resupply effort rather than an offensive reinforcement, but Confederate leaders saw any attempt to sustain the garrison as a challenge to their authority. On April 12, Confederate guns opened fire; Anderson surrendered after roughly 34 hours.
A common mix-up is Fort Pickens in Florida, which was also involved in an 1861 reinforcement crisis. Fort Sumter, however, was the fort whose bombardment conventionally marks the war’s opening.