The major war fought from 1861 to 1865 that was centered on slavery in the U.S. is the American Civil War. The conflict arose from deep-seated issues surrounding slavery, states' rights, and economic differences between the North and South. After several southern states seceded from the Union in response to Abraham Lincoln's election, armed hostilities broke out at Fort Sumter in 1861. The war led to significant loss of life and ultimately resulted in the abolition of slavery through the 13th Amendment. The Civil War fundamentally changed the nation, laying the groundwork for civil rights advancements in the future.