Census of 1870 - S.D. Jackman, Hays County, age 45, born circa 1825 in Kentucky, farmer.
Census of 1880 - Sidney D. Jackman, Hays County, age 54, born circa 1826 in Kentucky, farmer, wife Cass.
FamilySearch . 18801870
Confederate States Army, Colonel, Jackmans Regiment, Missouri Cavalry. Military grave marker, Sydney Drake Jackman, birth date 3/7/1826, death date 6/2/1886, burial in Kyle Cemetery, Kyle, Hays County.
Find a Grave .
Jackman's Missouri Cavalry. Confederate States Army, Colonel, 7th Missouri Infantry Regiment; Brigadier General, spring 1865.
Handbook of Texas Online .