What nation issued the $5 bill that was found in Abraham Lincoln's pocket after he was shot?

Abraham Lincoln had a $5 bill from the former Confederate States of America in his pocket when he was assassinated. Lincoln was assassinated in Ford's Theatre on April 14, 1865, less than one month before the Confederacy official dissolved and the states rejoined the United States.

In addition to the Confederate $5 bill, the night that Lincoln was shot he was also carrying a pocket knife, a handkerchief, a watch fob, two pairs of spectacles, a brown leather wallet and eight newspaper clippings, many related to his remarks on the war. The Library of Congress sometimes displays the collection of items from Lincoln's pockets.