premise: The American Civil War ended on May 8, 1865.
hypothesis: The Appomattox Campaign was a series of American Civil War battles fought March 29 -- April 9 , 1865 in Virginia that concluded with the surrender of Confederate General Robert E. Lee 's Army of Northern Virginia to the Union Army ( Army of the Potomac , Army of the James and Army of the Shenandoah ) under the overall command of Lieutenant General Ulysses S. Grant .