[Source: Descriptive rolls of 91st PA; National Archives and Record Administration]
[related page: officers in the 91st PA (Official Army Register)]
List of Commissioned Officers.
[A paper saying that only the descriptive list has been carded is at the bottom of the page; it claims that 172 names were carded]| [No.] | Names | Rank | Date of Appointment. | Remarks. |
| John F Casner | Capt | Sept 24th | Mustered in to the Service of the U States Decr 3d 1861 | |
| Lewis J Matlack | 1s Lieut | " " | " " " " Nov 25th | |
| Wm R. Miilligan | 2nd Lieut | " " | " " " Decr 3rd 1861 |