What treaty did Robert E lee signed when he surrender?

Answer 1

There was no treaty, and the Civil War was the first war that the US won without a treaty being signed. Although Abraham Lincoln had never demanded an unconditional surrender, and although Jefferson Davis had ordered Lee to continue fighting, Lee disobeyed that order and surrendered the Confederacy unconditionally. In return

Grant allowed terms which were very lenient, and it is sometimes supposed that a treaty was singned, but it was in fact an unconditional surrender.