James Calhoun (August 24, 1845 – June 25, 1876) was a soldier in the United States Army during the American Civil War and the Black Hills War. He was the brother-in-law of George Armstrong Custer and was killed along with Custer in the Battle of the Little Bighorn. His brother-in-law Myles Moylan survived the battle as part of the forces with Major Marcus Reno and Captain Frederick Benteen.