The war fought between the North and South in the United States from 1861 to 1865 is known as the American Civil War. This conflict arose primarily from disputes over slavery, states' rights, and economic differences, leading to tensions between the Northern states (Union) and the Southern states (Confederacy) that seceded from the Union. Key battles, such as Gettysburg and Antietam, and significant figures like Abraham Lincoln and Robert E. Lee played crucial roles throughout the war. Ultimately, the Union's victory preserved the nation, leading to the abolition of slavery and significant political, social, and economic changes in the post-war United States.