When Charles' parents died, his brothers George Washington Barnum and Henry Taylor Barnum, who had moved to Centerville, South Dakota, asked Charles to join them. He did, and there he met Helen Augusta Sitgreaves. They married on 25 November 1884, in Delaware, South Dakota. Their first child was a girl, who was born on 23 September 1885 in Centerville, SD, and died at birth. Their second child was also a girl, Ilba Sitgreaves Barnum, who was born on 23 August 1889 in Delaware, SD, and died on 3 March 1891, in Lead, SD where she is buried. Their third child was Sheldon Charles Barnum. Charles traveled between South Dakota and Connecticut many times, and had moved back to Connecticut when he died. He is buried in Bethel, Connecticut.