What event is considered the start of the American Civil War?

The firing on Fort Sumter is widely recognized as the start of the American Civil War because it marked the first military action of the conflict. On April 12, 1861, Confederate forces fired upon Fort Sumter, a Union fort in South Carolina, after the Union troops stationed there were ordered to maintain their position despite the growing tensions between the North and South over issues like slavery and states' rights. This attack galvanized the North's response, leading to President Abraham Lincoln calling for troops to suppress the rebellion, effectively igniting a four-year war that would reshape the nation.

In contrast, the signing of the Declaration of Independence occurred in 1776 and relates to the American Revolution rather than the Civil War. The Battle of Gettysburg, which took place in 1863, was one of the war's turning points but came after the conflict had already begun. The assassination of Lincoln in 1865 occurred after the Civil War had ended and does not mark the war's inception. Each of these events plays a significant role in American history, but the firing on Fort Sumter specifically signifies the beginning of hostilities in the Civil War.