A US holiday. Sort of. Try convincing your boss. It commemorates the freeing (on June 19, 1865, hence the name) of the last slaves on American soil, those in Texas - nearly three years after Abraham Lincoln's Emancipation Proclamation. A Union general, Gordon Granger, once the state had been successfully invaded and occupied, issued an order (General Order #3) in Galveston making the end of slavery official. Again.