# XXII Corps (Union Army)

XXII Corps was a corps in the Union Army during the American Civil War. It was created on February 2, 1863, to consist of all troops garrisoned in Washington, D.C., and included three infantry divisions and one of cavalry (under Judson Kilpatrick, which left to join the Army of the Potomac during the Gettysburg campaign). Many of its units were transferred to the Army of the Potomac during Grant's Overland Campaign.
This Corps did not include the many regiments that passed through Washington, D.C., on the way to the front or away from it. Nor does it include the many regiments from the Army of the Potomac, Army of Georgia, and Army of the Tennessee that encamped in the area to participate in the Grand Review of the Armies.

## History

Civil War Armies at the time took their name from the Department that it was born out of. This is the reason for the naming of the Army of the Potomac, born out of the Department of the Potomac. At the time of the war, the Union named most of its departments, and thus its armies, after naturally occurring landmarks, specifically water courses, i.e. The Army of the Potomac, The Army of the James, The Army of the Gulf, etc. In opposition, the Confederacy named most of their Armies for geographic areas and states.

### Department of the East

Comprising all of the United States east of the Mississippi River, about half of which became Confederate territory. Formed on January 1, 1861, there were many Departments formed within its borders, and finally destablished August 17, 1861. Its primary focus was to employ a chain of command to all units until the smaller departments could be formed. Headquartered in Albany, New York, it was commanded by Major General John E. Wool.

### Department of Washington, D.C.

Constituted April 9, 1861, to include Washington, D.C., to its original boundaries of Arlington, Virginia, and the state of Maryland as far as Bladensburg. It was formed to center on the defense of the national capital, and to differentiate it from the Department of the East. The department was commanded by Lieutenant Colonel Charles F. Smith from April 10 through April 28, 1861, and Colonel (later Brigadier General) Joseph K. Mansfield from April 28, 1861, through the Department's dissolution on July 25, 1861.

### Army of the Potomac

The Army of the Potomac, formed July 25, 1861, and destablished August 16, 1861, provide for the defense of the city of Washington, D.C. This Department was entrusted with the duty of protecting the United States' capital, with the construction of fortifications. Before the dissolution of the Department of the Potomac, most of the fortifications in the Washington, D.C., area were constructed, mainly by the regiments that were garrisoned there, most of whom had gone on to form the Army of the Potomac. Commanded by Major General George B. McClellan.

### Military District of Washington

A Military District during the Civil War was a formation within a Department for the purpose of reporting directly to the department commander for administrative affairs.
The Military District of Washington was organized June 26, 1862, to include Washington, D.C.; Alexandria, Virginia; and Fort Washington, Maryland. It was a District under the Department of the Potomac. It was incorporated into the Department of the Rappahanock from April 4, 1862, through June 26, 1862, when it again became an independent command. On February 2, 1863, it merged into the Department of Washington. Commanded by Brigadier General James S. Wadsworth.

### Department of the Rappahannock

The Department of the Rappahannock was formed April 4, 1862, from the original I Corps of the Army of the Potomac, to control the area east of the Blue Ridge Mountains to the Potomac River, the Fredericksburg and Richmond Rail Road and the District of Columbia expanded to include the area between the Potomac and Patuxent Rivers. It was merged into the Army of Virginia as III Corps on June 26, 1862, with Major General Irwin McDowell as its commander.

### Defenses of Washington, D.C.

The Defenses of Washington D.C. was a short lived command, from September 2, 1862, through February 2, 1863. used for the consolidation of all the defenses of the area including and surrounding Washington, D.C. Its main focus was on the maintaining of the fortifications in extending in a ring around Washington, D.C.

### Department of Washington

On February 2, 1863, the Department of Washington was re-formed to encompass the area from north of the Potomac from Piscataway Creek to Annapolis Junction (near present-day Fort Meade), west to the Monocacy River, south to the Bull Run Mountains by way of Goose Creek, then east to Occoquan River. The size of it would expand throughout the war to include the entirety of the counties in the surrounding states of Maryland and Virginia.
The Quartermaster Department of the Department of Washington was the largest Quartermaster Department in the Union Army. Duties as varied as building, maintenance of fortifications, supplies, road building, transportation, and ordnance testing as well as many other duties were taken over by the quartermasters of the Washington Department. Washington, D.C., also served as a transship point for supplies and materiel destined to both the Army of the Potomac and Army of the James.

### XXII Corps

A Corps is a grouping of two to six divisions, providing a level of the chain of command typically commanded by a major general. Corps were first created by an Act of Congress on July 17, 1862, but Major General George B. McClellan had instituted them in the spring of 1862. Before this time, the formations were known as either "Wings" or "Grand Divisions". Most Corps came under the operational command of an Army, but the XXII Corps did not.
XXII Corps was formed as a Corps under the Department of Washington on February 2, 1863. As was tradition, its commanders doubled as commanders of the Department of Washington. During its time, many of the regiments that were fought out arrived to reconstitute and would then be transferred back out, most of them from or to the Army of the Potomac.

## Battles
### Mosby's Raids

During the time of existence of the 43rd Battalion Virginia Cavalry, better known as Mosby's Rangers, Mosby's Command, or Mosby's Raiders, commanded by Colonel John S. Mosby, made many forays in the area known as Mosby's Confederacy which extended from Loudoun County to Fairfax County. Many of the raids it performed came into the area protected by XXII Corps, and many skirmishes with Brigadier General William Gamble's Cavalry Division, as well as various other XXII Corps units. During its reign, Mosby's Raiders captured Brigadier General Edwin H. Stoughton (then commanding the 2nd Vermont Brigade), cut telegraph wires during Early's Valley Campaign and numerous raids against rail lines and supply stations.

### Battle of Fort Stevens

The corps took part in the defense of Washington during Jubal Early's Washington Raid of 1864, playing a major role in the defense of Fort Stevens on July 11, 1864. Hardin's Division held the skirmish lines and engaged in small engagements, suffering 73 killed and wounded. The following day, Early found the works held by veteran soldiers of Major General Horatio Wright's VI Corps and Brevet Brigadier General William Emory's XIX Corps. After making a small fight, Early would withdraw, crossing back into Virginia the next day.

## Command history

| Major General Samuel P. Heintzelman | February 2, 1863 – October 13, 1863 |
| Major General Christopher C. Augur | October 13, 1863 – June 11, 1865 |
| Major General John G. Parke | June 7, 1865 – June 26, 1865 |

## Notable officers

| Name | Unit | Dates Served |
| Major General John G. Barnard | Chief Engineer, Department of Washington | July 1, 1862 — June 5, 1864 |
| Major General Silas Casey | Commanded Casey's Division (Provisional Brigade) and served as an administrative officer | June 1862 — May 1863 |
| Maj. Gen. George B. McClellan | Commanded Department of the Potomac | July 25, 1861 — August 16, 1861 |
| Major General Montgomery C. Meigs | Quartermaster General of the Union Army and commander of War Department clerks during the Battle of Fort Stevens | May 15, 1861 — June 30, 1865 |
| Brigadier General John Joseph Abercrombie | Commanded Abercrombie's Division | October 1862 — June 26, 1863 |
| Brigadier General Barton S. Alexander | Chief Engineer of the Defenses of Washington, D.C. | July 1, 1862 — April 7, 1863 |
| Brigadier General Robert Cowdin | Commanded 1st and 2nd Brigade, Abercrombie's Division | October, 1862 — March 30, 1863 |
| Brigadier General Gustavus Adolphus DeRussy | Commander of DeRussy's Division, stationed south of Washington, D.C. | May 25, 1863 — August 20, 1865 |
| Brigadier General Martin Davis Hardin | Commander of Haskin's Division, stationed north of Washington, D.C. | July 8, 1864 — August 2, 1865 |
| Brigadier General Joseph Abel Haskin | Commander of Haskin's Division, stationed north of Washington, D.C., later Chief of Artillery | February 2, 1863 — April 10, 1866 |
| Brigadier General William Gamble | Commanded Cavalry Division | December 21, 1863 — July 17, 1865 |
| Brigadier General Rufus King | Commanded King's Division | July 15, 1863 — October 20, 1863 |
| Brigadier General Joseph K. Mansfield | Commanded the original Department of Washington | April 28, 1861 — March 15, 1862 |
| Brigadier General Edwin H. Stoughton | Commander, 2nd Vermont Brigade | December 7, 1862 — March 9, 1863 |
| Colonel John Baillie McIntosh | Commander of Cavalry Division | January 2, 1864 — May 2, 1864 |
| Chief Aeronaut Thaddeus S. C. Lowe | Commander of the Union Army Balloon Corps | October 1861 — August 1863 |

## Components of XXII Corps

Many Regiments and Brigades serving in the XXII Corps were only temporarily assigned to it. Some mainly served during times when they were reconstituting due to battle casualties, while others were trained in the vicinity of Washington before going into the field. Yet others were heavy artillery regiments assigned to the fortifications surrounding the capital. Many units, including heavy artillery regiments, left when more soldiers were needed during Grant's Overland Campaign and continued through the Richmond-Petersburg Campaign until the end of the war. Some units began serving before the XXII Corps was formed.

### Famed Brigades in XXII Corps

The California Brigade was formed by Oregon Senator and Colonel Edwin Baker to have a California presence in the Eastern Theater. After the death of Colonel Baker at the Battle of Ball's Bluff, the brigade was redesignated the Philadelphia Brigade. Made up of the 1st, 2nd, 3rd, and 5th California Infantry. After redesignation as the Philadelphia Brigade, it consisted of the 69th, 71st, 72nd, and 106th Pennsylvania Infantry.
The First New Jersey Brigade was a Brigade formed by the state of New Jersey while defending Washington, D.C. This was the first brigade in the Civil War to be formed with the intention of encompassing regiments from one state. It consisted of the 1st, 2nd, 3rd, 4th, and 10th New Jersey Infantry. By the end of the war, at different it would have up to eight New Jersey regiments.
The Pennsylvania Reserve Division was formed out of an overflow of volunteers over the amount requested by the Department of War. After the Secretary of War declined to accept the new units into Federal Service, they were formed, equipped and maintained by the State of Pennsylvania. During its service in Washington, D.C., it was composed of the 3rd, 4th, and 8th Pennsylvania Reserves.
Vermont gave two brigades to the defenses of Washington, D.C. The 1st Vermont Brigade, composed of the 2nd, 3rd, 4th, and 6th Vermont Infantry. It was brigaded together through the efforts of Colonel William F. "Baldy" Smith who went to his West Point classmate and friend, Major General George B. McClellan.
The 2nd Vermont Brigade, composed of 12th, 13th, 14th, 15th, and 16th Vermont Infantry, all nine-month regiments, was formed October 27, 1862.
The Iron Brigade was the only named brigade to come from varied states, the 2nd, 6th, and 7th Wisconsin Infantry, along with the 19th Indiana Infantry and was formed on October 1, 1861. Although at the time, it wasn't known by this name, simply known as 3rd Brigade, I Corps. It wouldn't earn the moniker for almost a year, during the Battle of South Mountain during the Antietam Campaign.

### Connecticut

| Unit | Duration | Destination |
| 1st Connecticut Cavalry | April 29, 1865 — August 2, 1865 | Mustered out |
| 1st Connecticut Heavy Artillery | August 27, 1862 — May 13, 1864 | Overland Campaign |
| 2nd Connecticut Heavy Artillery | November 23, 1863 — May 13, 1864 | Overland Campaign |
| 2nd Connecticut Heavy Artillery | June 3, 1865 — August 18, 1865 | Mustered out |
| 2nd Connecticut Light Artillery | October 15, 1862 — June, 1863 | Gettysburg Campaign |
| 2nd Connecticut Light Artillery | October 12, 1863 — January, 1864 | Transfer to New Orleans, Louisiana |
| 5th Connecticut Infantry | May 20, 1865 — July 19, 1865 | Mustered out |
| 14th Connecticut Infantry | May 15, 1865 — May 21, 1865 | Mustered out |
| 19th Connecticut Infantry | September 16, 1862 — November 23, 1863 | Redesignated 2nd Connecticut Heavy Artillery |
| 22nd Connecticut Infantry | October 3, 1862 — April 14, 1863 | Siege of Suffolk |
| 29th Connecticut Infantry (Colored) | April 18, 1865 — May 28, 1865 | Transfer to Brownsville, Texas |

### Delaware

| Unit | Duration | Destination |
| Nield's Independent Battery Light Artillery | September, 1862 — April 18, 1863 | Transfer to Norfolk, Virginia |
| 1st Delaware Infantry | May 12, 1865 - July 12, 1865 | Mustered out |
| 3rd Delaware Infantry | May 12, 1865 — June 3, 1865 | Mustered out |
| 4th Delaware Infantry | May 12, 1865 — June 3, 1865 | Mustered out |
| 8th Delaware Infantry | May 12, 1865 — June 3, 1865 | Mustered out |

### District of Columbia

| Unit | Duration | Destination |
| 1st District of Columbia Cavalry | June, 1863 — January, 1864 | Transfer to Yorktown, Virginia |
| 2nd District of Columbia Infantry | September 22, 1862 — September 12, 1865 | Mustered out |

### Illinois

| Unit | Duration | Destination |
| 8th Illinois Cavalry | January 31, 1864 — July 1, 1865 | Transfer to Chicago, Illinois, to be mustered out |

### Indiana

| Unit | Duration | Destination |
| 16th Independent Battery Indiana Light Artillery | October 1, 1862 — June, 1865 | Transfer to Indiana to be mustered out |
| 19th Indiana Infantry | August 5, 1861 — March, 1862 | Bull Run Campaign (Part of the Iron Brigade) |
| 28th Indiana Infantry (Colored) | April 26, 1864 — July 1, 1864 | |
| 63rd Indiana Infantry | May 27, 1862 — August 16, 1862 | Bull Run Campaign |

### Maine

| Unit | Duration | Destination |
| 1st Maine Heavy Artillery | August 25, 1861 — May 15, 1864 | Overland Campaign |
| 2nd Maine Light Artillery | November 5, 1863 — April 25, 1864 | Overland Campaign |
| 3rd Maine Light Artillery | September, 1862 — July 5, 1864 | Richmond-Petersburg Campaign |
| 7th Maine Light Artillery | February 2, 1864 — April 25, 1864 | Overland Campaign |
| 15th Maine Infantry | April 23, 1865 — May 31, 1865 | Transfer to Savannah, Georgia |
| 23rd Maine Infantry | October 19, 1862 — June 17, 1863 | Transfer to Maine to muster out (9 month regiment) |
| 25th Maine infantry | October 18, 1862 — June 30, 1863 | Transfer to Maine to muster out (9 month regiment) |
| 27th Maine Infantry | October 20, 1862 — July 4, 1863 | Transfer to Maine to muster out (9 month regiment) |
| 31st Maine Infantry | April 19, 1864 — May 3, 1864 | Overland Campaign |
| 32nd Maine Infantry | April 21, 1864 — May 3, 1864 | Overland Campaign |

### Maryland

| Unit | Duration | Destination |
| Battery "D" Maryland Light Artillery | June, 1864 — June 25, 1865 | Mustered out |
| Baltimore Independent Battery Light Artillery | January, 1865 — June 17, 1865 | Mustered out |

### Massachusetts

| Unit | Duration | Destination |
| 2nd Massachusetts Cavalry | July 29, 1863 — July 14, 1864 | Pursuit of Early |
| 3rd Massachusetts Cavalry | April 20, 1865 — June 14, 1865 | Transfer to St. Louis, Missouri |
| 5th Massachusetts Cavalry | May 8, 1864 — May 12, 1864 | Petersburg - Richmond Campaign |
| 5th Massachusetts Cavalry | June 30, 1864 — March, 1865 | Transfer to Richmond, Virginia |
| 1st Massachusetts Heavy Artillery | January 1, 1862 — May 15, 1864 | Overland Campaign |
| 1st Massachusetts Heavy Artillery | May 23, 1865 — August 17, 1865 | Mustered out |
| 3rd Massachusetts Heavy Artillery | August, 1864 — September 18, 1865 | Mustered out |
| 4th Massachusetts Heavy Artillery | November 12, 1864 — June 17, 1865 | Mustered out |
| 7th Massachusetts Light Artillery | July 22, 1863 — August 18, 1863 | New York Draft Riots |
| 7th Massachusetts Light Artillery | September 11, 1863 — January 24, 1864 | Transfer to New Orleans, Louisiana |
| 9th Massachusetts Light Artillery | September 4, 1862 — June 25, 1863 | Gettysburg Campaign |
| 10th Massachusetts Light Artillery | October 17, 1862 — June 24, 1863 | Gettysburg Campaign |
| 11th Massachusetts Light Artillery | November 4, 1862 — May 25, 1863 | Transfer to Boston, Massachusetts, to be mustered out (9 month regiment) |
| 11th Massachusetts Light Artillery (Reorganized) | February 6, 1864 — April 9, 1864 | Overland Campaign |
| 16th Massachusetts Light Artillery | April 18, 1864 — July 1, 1865 | Transferred to Massachusetts, to be mustered out |
| 40th Massachusetts Volunteer Infantry | September 8, 1862 — April 15, 1863 | Transferred with division to Department of Virginia and North Carolina |

### New Hampshire

| Unit | Duration | Destination |
| 14th New Hampshire Infantry | October, 1862 — March, 1864 | |

### New Jersey

| Unit | Duration | Destination |
| 2nd New Jersey Cavalry | October 25, 1864 — November 9, 1863 | |
| 10th New Jersey Infantry | December 26, 1861 — April, 1863 | |

### New York

| Unit | Duration | Destination |
| 9th New York Heavy Artillery | September, 1862 — May 18, 1864 | |
| 11th New York Infantry | May 7, 1861 — July 15, 1861 | |

### Ohio

| Unit | Duration | Destination |
| 131st Ohio Infantry (Detachments from) | May 15, 1864 — August 19, 1864 | |

### Pennsylvania

| Unit | Duration |
| 2nd Pennsylvania Heavy Artillery | February 26, 1862 — May 28, 1864 |
| 5th Pennsylvania Heavy Artillery | September 14, 1864 — June 30, 1865 |
| 6th Pennsylvania Heavy Artillery | September 15, 1864 — June 15, 1865 |

### Vermont

| Unit | Duration |
| 10th Vermont Infantry | September 8, 1862 — June 22, 1863 |
| 11th Vermont Infantry | September 22, 1862 — May 15, 1864 |
| 12th Vermont Infantry | October 10, 1862 — June 25, 1863 |
| 13th Vermont Infantry | October 13, 1862 — June 25, 1863 |
| 14th Vermont Infantry | October 25, 1862 — June 25, 1863 |
| 15th Vermont Infantry | October 26, 1862 — June 25, 1863 |
| 16th Vermont Infantry | October 27, 1862 — June 25, 1863 |

### United States Volunteers

| Unit | Duration |
| Veteran Reserve Corps | |
| 1st Battalion, Veteran Reserve Corps | |
| 2nd Battalion, Veteran Reserve Corps | |
| Union Army Balloon Corps | October, 1861 — August, 1863 |