< to August • September 1863 • to October >
Commanded by Major General Samuel P. Heintzelman
| Defences North of the Potomac | Lieutenant Colonel Joseph A. Haskin | |
| First Brigade | Colonel August A. Gibson | |
| 2nd Pennsylvania Heavy Artillery | Colonel August A. Gibson | |
| 1st Vermont Heavy Artillery | Colonel James M. Warner | |
| Second Brigade | Colonel Lewis O. Morris | |
| 1st Maine Heavy Artillery | ||
| 7th New York Heavy Artillery | Colonel Lewis O. Morris | |
| 9th New York Heavy Artillery | ||
| 9th New York Independent Battery | ||
| Third Brigade | Colonel A. Piper | |
| 10th New York Heavy Artillery | ||
| Defences South of the Potomac | Brigadier General Gustavus A. DeRussy |
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| First Brigade | Colonel J.N.G. Whistler (to 9/16) Colonel T. R. Tannatt |
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| 1st Massachusetts Heavy Artillery | ||
| 2nd New York Heavy Artillery | ||
| 5th New York Heavy Artillery, Companies I,K,L&M |
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| Second Brigade | Colonel L. W. Wessells (to 9/20) Colonel L. Schirmer |
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| 19th Connecticut Infantry Regiment | Colonel Leverette Wessells | serving as heavy artillery |
| 3rd New York Heavy Artillery Battalion | Lieutenant Colonel Adam Senges | |
| Third Brigade | Colonel H. L. Abbot | |
| 1st Connecticut Heavy Artillery | Colonel Henry L. Abbott | |
| 1st Rhode Island Artillery, Battery H | ||
| 1st Wisconsin Heavy Artillery, Bat. A | ||
| Fourth Brigade | Lieutenant Colonel T. Allcock (to 9/2) Colonel J.C. Tidball |
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| 2nd Massachusetts Cavalry Regiment | ||
| 4th New York Heavy Artillery | Colonel H. H. Hall | |
| King’s Division | Brigadier General Rufus King | |
| 1st Brigade (“Corcoran Legion”) | Brigadier General Michael Corcoran | |
| 155th New York Infantry Regiment | Colonel William McEvily | |
| 164th New York Infantry Regiment | Colonel James McMahon | |
| 170th New York Infantry Regiment | Colonel James D. McIvor | |
| 182nd New York Infantry Regiment | Colonel Mathew Murphy | |
| Not Brigaded | ||
| 4th Delaware Infantry Regiment | Colonel A.H. Grimshaw | |
| 17th New York Independent Battery | ||
| 157th Pennsylvania Infantry (4 cos.) | ||
| District of Washington | Brigadier General J. H. Martindale (to 9/16) Major J. P. Sherborne (9/16) Colonel M. N. Wisewell |
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| 2nd District of Columbia Infantry Regiment | Colonel Charles M. Alexander | |
| 14th New Hampshire Infantry Regiment | Colonel Robert Wilson | |
| 153rd New York Infantry Regiment | Colonel Edwin P. Davis | |
| 178th New York Infantry Regiment | Lieutenant Colonel Charles F. Smith | |
| 150th Pennsylvania Infantry, Co. K | Captain David Derickson | Lincoln’s Bodyguard |
| 157th Pennsylvania Infantry (4 cos.) | ||
| District of Alexandria | Brigadier General John P. Slough | |
| Slough’s Independent Brigade | Brigadier General John P. Slough | |
| 1st District of Columbia Infantry Regiment | ||
| Pennsylvania Independent Battery H | ||
| Second Brigade, Pennsylvania Reserves | Colonel Horatio G. Sickel Colonel H. C. Bollinger |
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| 3rd Pennsylvania Reserves Regiment | Lieutenant Colonel John Clark | |
| 4th Pennsylvania Reserves Regiment | Colonel Richard H. Woolworth | |
| 7th Pennsylvania Reserves Regiment | Colonel Henry C. Bolinger | |
| 8th Pennsylvania Reserves Regiment | Colonel Silas M. Baily | |
| Independent Cavalry Brigade | Colonel C. R. Lowell, Jr. | |
| 2nd Massachusetts Cavalry Regiment | ||
| 13th New York Cavalry (Companies A-F) | Lieutenant Colonel Henry S. Gansevoort | |
| 16th New York Cavalry (Companies A-D) | ||
| Light Artillery Camp (Camp Barry) | ||
| 7th Massachusetts Battery | ||
| 10th Michigan Battery | to Army Potomac, 11 Corps Art. | |
| 1st New York Artillery, Battery F | ||
| 1st New York Artillery, Battery H | ||
| 10th New York Independent Battery | Lieutenant Charles T. Bruen | |
| 19th New York Independent Battery | . | |
| 12th Ohio Independent Battery | to Army Potomac Artillery Res., 1 Vol. Brig. | |
| 1st Pennsylvania Artillery, Battery H | ||
| 1st West Virginia Artillery, Battery F | ||
| 5th United States Artillery, Battery I | ||
| 5th United States Artillery, Battery L |