While in Cheyenne, he married Agnes Lake Thatcher, owner of a circus, in 1876. They honeymooned in Cincinnati. From there he went on to Deadwood, South Dakota in the summer of 1876.
It was a gold rush boom town then. There were 25,000 people, one of which was Calamity Jane. On August 2, 1876, Wild Bill sat down for a poker game at Nuttall & Mann's No. 10 saloon. At the table were Carl Mann, owner of the saloon, Captain William R. Massic, a former Missouri River pilot, and Charles Rich, a gambler, gunman, and friend of Wild Bill's. For the first time, he was sitting with his back to the door instead of to a wall. Jack McCall, a 25 year old drifter, shot Wild Bill in the back of the head, to enhance his own reputation. At the time he died, Wild Bill was holding two black aces, two black eights, and the jack of diamonds, now forever called "the deadman's hand."
McCall was tried the next day, but acquired. His defense was that he was getting revenge for his brother, who Wild Bill had supposedly killed in Kansas. He was later tried again, his first trial being declared illegal since it took place in Indian territory. He was convicted and hung on March 1, 1877.