- Born: 1707 Scotland
- Married: Elizabeth Alexander (Ireland, of Scottish descent)
From Hamilton 1979
- John Duncan (c1744-1818)
- Elizabeth Duncan (c1750-1845) = Samuel Porter (1735-c1820) and lived at Castlewood, in Russell County, Virginia.
- Martha Duncan = Solomon Litton and lived at Elk Garden, Russell County.
- Mary Jane Duncan = James Laughlin, son of John and Mary Price Laughlin, and lived in Washington County, Virginia.
- There was a younger sister (name unknown) who married a Mr. Robinson in Russell County, Virginia, and later returned to Pennsylvania.