| Birth | 27 Nov 1887 | West Plains, Howell Co., MO | | | |
| Census | 1 Jun 1900 | Howell Twp., Howell Co., MO, ED 54 Sh 15A; Willie J. Duncan, son, born Nov 1887, 12, born MO father born IL mother born MO. | | | |
| Marriage | 28 Jun 1908 | Lillie Mae SHOUPE | | | |
| Census | 15 Apr 1910 | Howell Twp., Howell Co., MO, ED 81 Sh 10B; William J. Duncan, head, 22 (1887-88), marriage 1 of 1 yr., born MO father born IL mother born MO. | | | |
| Military | Bet 1917 and 1918 | World War I Draft Reg. card: William Joseph Duncan, born Nov 27, 1887 | | | |
| Census | 1 Jan 1920 | Lester Twp., Okfuskee Co., OK, ED 146 Sh 6B; William Duncan, head, 32 (1887), married, born MO father born IL mother born MO, farmer. | | | |
| Census | 1 Apr 1930 | Morse Twp., Okfuskee Co., OK, ED 11 Sh 10A; William J. Duncan, head, 42 (1887-88), 20 at first marriage, born MO father born IL mother born MO, farmer. | | | |
| Death | Nov 1956 | | | | |
| Reference No | | 7171 | | | |