American Civil War: Battle of Fort Sumter. The war begins with Confederate forces firing on Fort Sumter, in the harbor of Charleston, South Carolina.

The Battle of Fort Sumter (April 1213, 1861) was the bombardment of Fort Sumter near Charleston, South Carolina by the South Carolina militia. It ended with the surrender by the United States Army, beginning the American Civil War.

Following the declaration of secession by South Carolina on December 20, 1860, its authorities demanded that the U.S. Army abandon its facilities in Charleston Harbor. On December 26, Major Robert Anderson of the U.S. Army surreptitiously moved his small command from the vulnerable Fort Moultrie on Sullivan's Island to Fort Sumter, a substantial fortress built on an island controlling the entrance of Charleston Harbor. An attempt by U.S. President James Buchanan to reinforce and resupply Anderson using the unarmed merchant ship Star of the West failed when it was fired upon by shore batteries on January 9, 1861. South Carolina authorities then seized all Federal property in the Charleston area except for Fort Sumter.

During the early months of 1861, the situation around Fort Sumter increasingly began to resemble a siege. In March, Brigadier General P. G. T. Beauregard, the first general officer of the newly formed Confederate States Army, was placed in command of Confederate forces in Charleston. Beauregard energetically directed the strengthening of batteries around Charleston harbor aimed at Fort Sumter. Conditions in the fort deteriorated due to shortages of men, food, and supplies as the Union soldiers rushed to complete the installation of additional guns.

The resupply of Fort Sumter became the first crisis of the administration of U.S. President Abraham Lincoln, inaugurated March 4, 1861, following his victory in the election of November 6, 1860. He notified the Governor of South Carolina, Francis W. Pickens, that he was sending supply ships, which resulted in an ultimatum from the Confederate government for the immediate evacuation of Fort Sumter, which Major Anderson refused. Beginning at 4:30 a.m. on April 12, the Confederates bombarded the fort from artillery batteries surrounding the harbor. Although the Union garrison returned fire, they were significantly outgunned and, after 34 hours, Major Anderson agreed to evacuate. There were no deaths on either side as a direct result of this engagement, although a gun explosion during the surrender ceremonies on April 14 caused the death of two U.S. Army soldiers. The event often regarded as the "First Bloodshed of the Civil War" was the Baltimore riot of 1861, one week later.

Following the battle, there was widespread support from both North and South for further military action. Lincoln's immediate call for 75,000 volunteers to suppress the rebellion resulted in an additional four Southern states also declaring their secession and joining the Confederacy. The battle is usually recognized as the first battle of the American Civil War.

The American Civil War (April 12, 1861 – May 9, 1865; also known by other names) was a civil war in the United States between the Union (states that remained loyal to the federal union, or "the North") and the Confederacy (states that voted to secede, or "the South"). The central cause of the war was the status of slavery, especially the expansion of slavery into territories acquired as a result of the Louisiana Purchase and the Mexican–American War. On the eve of the Civil War in 1860, four million of the 32 million Americans (~13%) were enslaved black people, almost all in the South.The practice of slavery in the United States was one of the key political issues of the 19th century. Decades of political unrest over slavery led up to the Civil War. Disunion came after Abraham Lincoln won the 1860 United States presidential election on an anti-slavery expansion platform. An initial seven southern slave states declared their secession from the country to form the Confederacy. Confederate forces seized federal forts within territory they claimed. The last-minute Crittenden Compromise tried to avert conflict but failed; both sides prepared for war. Fighting broke out in April 1861 when the Confederate army began the Battle of Fort Sumter in South Carolina, just over a month after the first inauguration of Abraham Lincoln. The Confederacy grew to control at least a majority of territory in eleven states (out of the 34 U.S. states in February 1861), and asserted claims to two more. Both sides raised large volunteer and conscription armies. Four years of intense combat, mostly in the South, ensued.

During 1861–1862 in the war's Western Theater, the Union made significant permanent gains—though in the war's Eastern Theater the conflict was inconclusive. On January 1, 1863, Lincoln issued the Emancipation Proclamation, which made ending slavery a war goal, declaring all persons held as slaves in states in rebellion "forever free." To the west, the Union destroyed the Confederate river navy by the summer of 1862, then much of its western armies, and seized New Orleans. The successful 1863 Union siege of Vicksburg split the Confederacy in two at the Mississippi River. In 1863, Confederate General Robert E. Lee's incursion north ended at the Battle of Gettysburg. Western successes led to General Ulysses S. Grant's command of all Union armies in 1864. Inflicting an ever-tightening naval blockade of Confederate ports, the Union marshaled resources and manpower to attack the Confederacy from all directions. This led to the fall of Atlanta in 1864 to Union General William Tecumseh Sherman and his march to the sea. The last significant battles raged around the ten-month Siege of Petersburg, gateway to the Confederate capital of Richmond.

The Civil War effectively ended on April 9, 1865, when Confederate General Lee surrendered to Union General Grant at the Battle of Appomattox Court House, after Lee had abandoned Petersburg and Richmond. Confederate generals throughout the Confederate army followed suit. The conclusion of the American Civil War lacks a clean end date: land forces continued surrendering until June 23. By the end of the war, much of the South's infrastructure was destroyed, especially its railroads. The Confederacy collapsed, slavery was abolished, and four million enslaved black people were freed. The war-torn nation then entered the Reconstruction era in a partially successful attempt to rebuild the country and grant civil rights to freed slaves.

The Civil War is one of the most studied and written about episodes in the history of the United States. It remains the subject of cultural and historiographical debate. Of particular interest is the persisting myth of the Lost Cause of the Confederacy. The American Civil War was among the earliest to use industrial warfare. Railroads, the telegraph, steamships, the ironclad warship, and mass-produced weapons saw wide use. In total the war left between 620,000 and 750,000 soldiers dead, along with an undetermined number of civilian casualties. President Lincoln was assassinated just five days after Lee's surrender. The Civil War remains the deadliest military conflict in American history. The technology and brutality of the Civil War foreshadowed the coming World Wars.