| Birth | May 1847 | St. Clair Co., Illinois | | | |
| Census | 1 Jun 1850 | Actual enumeration date 12 Nov 1850, Twelve Mile Prairie, Dist. 8, St. Clair Co., IL, pg. 202; Sylvester Duncan, 3 (1846-47), born St. Clair County. | | | |
| Census | 1 Jun 1860 | P.O. Freeburgh, Twp. 2 Range 7, St. Clair Co., IL, pg. 155; Sylvester Duncan, 12 (1847-48) born IL. | | | |
| Census | 1 Jun 1870 | P.O. New Athens, Twp. 2 Range 7, St. Clair Co., IL, pg. 9; Sylvester Duncan, 22 (1847-48), born IL, farmer. Living with parents. | | | |
| Census | 1 Jun 1880 | Twp. 2 Range 7, St. Clair Co., IL, ED 61 pg. 23B; Sylvester Dunkan [sic], relationship omitted, 28 (1851-52), born IL both parents born NC. In household of Jane Dunkan. Henry Duncan, 4, Jane's grandson, is also living with her & listed after Sylvester. | | | |
| Marriage | 4 Jan 1882 | Howell Co., MO - Martha K. BAILEY | |  | |
| Census | 1 Jun 1900 | Delaware Twp., Shannon Co., MO, ED 115 Sh 2B; Sylvester Duncan, head, born May 1847, 53, married 18 yr., born IL father born TN mother born IL, farmer. | | | |
| Death | Aft 1 Jun 1900 | | | | |
| Reference No | | 7125 | | | |