(Answer #2). The significance of Fort Sumter is that it is where the Civil War essentially started. When the Union tried to resupply the fort and the South fired on the fort, the war was inevitable. Fort Sumter was a fort in the harbor of Charleston, SC. Even after South Carolina seceded from the Union, Pres.ort Sumter, located in Charleston, South Carolina was one of two federal ports in the southern United States. Soon after the election of 1860 seven southern states succeeded from the Union.