James Calhoun was a soldier in the United States Army during the American Civil War and the Black Hills War. He was the brotherinlaw of George Armstrong Custer and was killed along with Custer in the Battle of the Little Bighorn. His brotherinlaw Myles Moylan survived the battle as part of the forces with Major Reno and Captain Benteen.
Calhoun was born in Cincinnati, Ohio into a prestigious and wealthy merchant family that included his brother Frederick. When the American Civil War broke out, he was travelling in Europe and two years later, both joined the Union army. Both brothers were to forgo the merchant life for the frontier to the dismay of their parents.
Source: Wikipedia