|The oldest man known was 56, and the youngest was 13.|
According to paragraph 929 of the Revised army regulations of 1861, enlistees were supposed to be more than 18, and less than 35. This rule, however, did not apply to musicians or to people who were reenlisted. Enlistment of anyone less than 21 required their parents', guardians', or master's permission.
The oldest enlisted men in company E claimed to be 44 when they enlisted, including George Hollick, William Lowry, John Thompson, Joseph Rementer, and Joseph Lathrop (44-1/2). And Wade Laconia (E), who claimed he was 37 when he enlisted, was discharged because he admitted a few months later that he was 53 years old! And Robert Gray (C) was supposedly 56, and lied about his age to be enlisted. (The Pennsylvania Archives Civil War Service card lists his age as 40, but the company A descriptive roll lists it as 58.)
Edward Flanagan (I) also claimed to be 44, but his death certificate lists his age as 90 in 1892, which makes his age approximately 59 at enlistment.
At least twelve, and possibly 21, men were discharged because they were under age. Several people were 16 when they enlisted, including William Reiff (H), who later claimed to have enlisted on his sixteenth birthday, and James Forsythe (D). The youngest person I know of was George Black, who was 13 when he enlisted to serve with his father.
The mean age at enlistment was 27.4 years, the median was 25, and more men were 18 than any other age.
On average, substitutes were younger, and drafted men were older, than volunteers.