Born: 1807-05-10 Kentucky
Died: 1856-07-09 Sangamon County, Illinois
Flourished: Sangamon County, Illinois
Brother of Marshal T. Duncan, and twin brother of William T. H. Duncan, James was born in Cumberland County, Kentucky. By 1821, James had emigrated with his father, Marshal Duncan, and siblings to Sangamon County, Illinois. In 1829, he married Mary Penny and they settled near present-day Salisbury, where they farmed and raised nine children.
U.S. Census Office, Sixth Census of the United States (1840), Sangamon County, IL, 27; John C. Power and S. A. Power, History of the Early Settlers of Sangamon County, Illinois (Springfield, IL: Edwin A. Wilson, 1876), 270-71.