The American Civil War was fought between the North (the Union) and the South (the Confederacy) from 1861 to 1865. This conflict arose primarily from tensions surrounding slavery, states' rights, and economic differences. The war resulted in significant social, political, and economic changes in the United States, including the abolition of slavery. Major battles, including Gettysburg and Antietam, defined the war's course, and it ultimately ended with the surrender of Confederate General Robert E. Lee. The Civil War left a lasting legacy on American society and continues to be studied for its profound impact on the nation.