Duncan married Susanne Istagiwin Hazahotawin Pennishon between 1796 and 1802 in Minnesota, USA. Susanne (daughter of Jean Pennishon and Winona Wapasha) was born about 1785 in Rum River, Mille Lacs, Minnesota, USA; died on 02 Mar 1848 in Mendota, Dakota, Minnesota, USA; was buried in 1865 in Calvary Cemetery, Faribault, Rice, Minnesota, USA. [Group Sheet] [Family Chart]

1. Marie Elizabeth Graham was born on 15 Jul 1804 in Sauk Rapids, Benton, Minnesota, USA; died on 08 Apr 1876 in Elizabeth, Otter Tail, Minnesota, USA; was buried in 1879 in Calvary Cemetery, Faribault, Rice, Minnesota, USA.
2. Lucy Nancy Graham was born in Sep 1805 in Mendota, Dakota, Minnesota, USA; died on 26 Sep 1888 in Fort Totten, Benson, North Dakota, USA; was buried on 29 Sep 1888 in St Felix Cemetery, Wabasha, Wabasha, Minnesota, USA.
3. Sarah Marie Graham was born in 1811 in Minnesota, USA; died about 1841 in Wabasha, Wabasha, Minnesota, USA; was buried in 1841 in St Felix Cemetery, Wabasha, Wabasha, Minnesota, USA.
4. Jane Graham was born in 1817 in St Peter's River, Dakota, Minnesota, USA; died in 1881 in Lake Pepin, Goodhue, Minnesota, USA.
5. Alexander Graham, Sr. was born on 15 Oct 1821 in Minnesota Territory, USA; died about 1865.