| 1 | 2 | 3 | 4 | 5 | 6 | 7 | ||
 May 1862 |
8 | 9 | 10 | 11 | 12 | 13 | 14 |  July 1862 |
| 15 | 16 | 17 | 18 | 19 | 20 | 21 | ||
| 22 | 23 | 24 | 25 | 26 | 27 | 28 | ||
| 29 | 30 |
The 91st was attached to the defenses of Washington, and had duty at Alexandria Virginia, throughout this month. [Dyer, v.3 p.1604]
| 1 |
Thomas Aitken (A) died of exposure at Alexandria VA (perhaps 10th)
George Henhoffer (A) discharged at Alexandria VA on surgeon's certificate (perhaps 10th) William Van Howden (F) discharged at Alexandria VA on surgeon's certificate (probably 12th) William Clages (C) deserted at Washington DC (possibly 20 Apr) David Lindsay (C) deserted at Washington DC (possibly 20 Apr) Charles Lowery (C) deserted, at Washington DC John McNickle (C) deserted at Washington DC (perhaps 25 Apr 62) |
| 2 | John Johnson (B) discharged |
| 3 | Ansel Hamburg (A) resigned on surgeon's certificate |
| 4 |
Matthew McNamara (I) discharged on surgeon's certificate
Stephen Nice (I) discharged on surgeon's certificate |
| 5 | William H Smith (C) deserted (perhaps 30th) |
| 6 | |
| 7 | |
| 8 | Frederick Heilman (I) deserted |
| 9 | |
| 10 |
Thomas Aitken (A) died of exposure at Alexandria VA (perhaps 1st)
Randolph Smith (A) promoted from 1st sgt to 2nd lt (possibly 11th or 12th) Joseph Wright (A) discharged at Alexandria VA on surgeon's certificate (perhaps 18th) James Manniess (E) discharged on surgeon's certificate James Nugent (F) reduced to the ranks George Henhoffer (A) discharged at Alexandria VA on surgeon's certificate (perhaps 1st) George Ubil (I) discharged on surgeon's certificate |
| 11 |
Randolph Smith (A) promoted from 1st sgt to 2nd lt (possibly 10th or 12th)
George Alcorn (F) deserted from Alexandria VA William Giger (F) promoted to corp Samuel Lamb (F) promoted to corp Ralph B Montgomery (F) deserted from Alexandria VA Michael S Snyder (E) discharged on surgeon's certificate Oscar Foust (F) deserted from Alexandria VA Kingsley Wyles (F) deserted from Alexandria VA John Zehender (F) promoted from corp to sgt (possibly 11 Jan 62) |
| 12 |
Randolph Smith (A) promoted from 1st sgt to 2nd lt (possibly 10th or 11th)
John Brass (A) promoted from sgt to orderly sgt Simon Shannon (F) discharged at Alexandria VA on surgeon's certificate William Van Howden (F) discharged at Alexandria VA on surgeon's certificate (probably 1st) Henry McKnight (G) discharged on surgeon's certificate, at regimental hospital, Alexandria VA |
| 13 | |
| 14 |
Colonel Gregory ordered the Baptist Church taken for use as a military hospital, because the pastor was unwilling to pray for Lincoln and Union success
[see 'A secess church shut up'] |
| 15 | |
| 16 |
Charles Clark (F) discharged from Philadelphia PA on surgeon's certificate (probably 16 Jan)
John Ennis (F) discharged from Philadelphia PA on surgeon's certificate (probably 16 Jan) |
| 17 | |
| 18 |
Robert Caldwell mustered in co G at Philadelphia PA and deserted
Joseph Wright (A) discharged at Alexandria VA on surgeon's certificate (perhaps 10th) William Whitman (D) died of typhoid fever, at Alexandria VA Isaac Thomas (D) promoted to corp Robert Boyd (F) reduced to the ranks (perhaps 16 Jul 62) Cornelius Dougherty (F) discharged at Alexandria VA on surgeon's certificate (possibly 18 May) |
| 19 |
John de Barry mustered in co G
Edwin Hause (F) promoted to corp |
| 20 | |
| 21 |
John McCann (F) deserted from Alexandria VA
Peter Van Buren (F) deserted from Alexandria VA (perhaps 27th) James Stratton mustered in co G Alvin Clark (G) transferred to 27th Mass Vol Inf (possibly 25th) Newton Wallace (G) transferred to 27th Mass |
| 22 | Joseph Allison enlisted and mustered in co E, at Alexandria VA (possibly 23rd) |
| 23 |
Joseph Allison enlisted and mustered in co E, at Alexandria VA (possibly 22nd)
William M Weaver discharged at Philadelphia on surgeon's certificate |
| 24 | Thomas Allison mustered in co E (according to Bates, not descriptive roll) |
| 25 | Alvin Clark (G) transferred to 27th Mass Vol Inf (probably 21st) |
| 26 | |
| 27 |
Robert McMullin mustered in co B
Peter Van Buren (F) deserted from Alexandria VA (perhaps 21st) |
| 28 |
Frederick Henhoffer (A) discharged at Alexandria VA on surgeon's certificate (perhaps 29th)
John Downey (C) discharged at Washington DC on surgeon's certificate Adolph Bankerd mustered in 62nd PA (probably 28 Jan 62) |
| 29 |
Frederick Henhoffer (A) discharged at Alexandria VA on surgeon's certificate (perhaps 28th)
John McCann (F) returned to duty from desertion the commissioned officers issued a "card" (later published in the Philadelphia Inquirer) denying "false and discreditable" accusations that the commissioned officers were nearly at open mutiny, that the regiment was reduced to 400 men, that Col. Gregory was excessively harsh to men in the regiment and excessively lenient to Confederates |
| 30 |
William Carpenter (B) dropped from rolls as deserter
John Haines (B) dropped from rolls William H Smith (C) deserted (perhaps 5th) |
| 31 |
