U.S. I Corps

The I Corps (First Corps) —nicknamed America's Corps— is a corps of the United States Army with headquarters in Fort Lewis, Washington. The I Corps serves under the U.S. Army Pacific Command (USARPAC) and has a distinguished history dating back to the American Civil War.

History

The Civil War

Main article: I Corps (ACW)

In the American Civil War, the I Corps was probably the most distinguished and veteran corps in the entire Union Army. It was commanded by very distinguished officers. It was created in March 1862, when President Abraham Lincoln ordered the creation of a four-corps army, then under the command of Major General George B. McClellan. The first commander of this corps was Major General Irvin McDowell, containing three divisions. It was held in defense of Washington, while the rest of the Army of the Potomac advanced to the Peninsula Campaign.

It was then consolidated in the Army of Virginia under Major General John Pope, and fought in the Second Battle of Bull Run, as the Third Corps, Army of Virginia. Afterwards, its name was restored. Then, it rejoined the Army of the Potomac, and crossed the Potomac River into Maryland to fight in the Battle of Antietam, under Major General Joseph Hooker. There, the division of Pennsylvania Reserves , under Brigadier General George G. Meade, took heavy casualties through its hard fighting, and was withdrawn to replenish.

The command of the Army of the Potomac then changed to Major General Ambrose E. Burnside, and they moved southward to fight General Robert E. Lee's army at the Battle of Fredericksburg, where the corps was commanded by Major General John F. Reynolds, arguably the best eastern Union corps commander. He superbly led the corps through this battle, then through the Battle of Chancellorsville, with the army being led by General Hooker, who left this superb corps in reserve.

In its last major battle, the Battle of Gettysburg, General Reynolds was killed just as the first troops arrived on the field, and command was inherited by Major General Abner Doubleday. Although putting up a ferocious fight, the I Corps was overwhelmed by the Confederate Third Corps (A.P. Hill) and forced to retreat through the town of Gettysburg, taking up defensive positions on Cemetery Hill. The next day (July 2, 1863), the command was given to Major General John Newton, a division commander from the VI Corps, who led it through this battle, including the defense against Pickett's Charge, and through the Mine Run Campaign that fall. Afterwards, the I Corps was disbanded and its units were reorganized and absorbed into the rest of the army, now led by Lieutenant General Ulysses S. Grant. The Civil War career of the I Corps was ended.

The Spanish-American War

The corps was reactivated in 1898, under the leadership of Major General John R. Brooke , and elements landed on July 31, 1898 to take part in the Puerto Rico Campaign . It advanced to Guayam , where it fought a battle on August 5, but the armistice was signed before they could partake in a slated major attack.

World War I

Following the American declaration of war on the country of Germany, on April 6, 1917, the I Corps was the first unit activated, and moved into the war in Europe. Its subordinate units were shipped to Europe, and the Corps was deactivated. However, it was reactivated again on January 15, 1918, in Neufchateau, France. Assisted by the French XXXII Corps , the headquarters was organized and trained; on January 20, Major General Hunter Liggett took command.

In February, the corps consisted of the 1st, 2nd, 26th , 32nd , 41st, and 42nd Divisions. From February to July, 1918, the German Army launched four major offensives, attempting to secure victory before the full American force could be brought to bear. The final offensive, started in July 1918, was an attempt to cross the Marne, in the area of Chateau-Thierry, but the American lines (including I Corps) held, and the offensive was fought back. Thereafter, the I Corps, along with other U.S. and Allied units, moved forward, breaking the German will to fight, until the armistice, signed on November 11, 1918.

The I Corps continued to train in France, until it was deactivated on March 25, 1919.

Sub-Units

1st, 2nd, 3rd, 4th, 5th, 6th, 26th, 28th, 32nd, 35th, 36th, 41st, 43rd, 77th, 78th, 80th, 82nd, 90th, 91st, and 92nd American Divisions.

62nd, 167th, and 5th Cavalry French Divisions.

World War II

During WWII, the corps fought in the South West Pacific Area. Its initial operations were in Papua, reinforcing Australian forces, which had turned back Japanese attacks along the Kokoda Track. The Allied forces then took the offensive, against the Japanese beachheads at Buna and Gona.

Thereafter, I Corps engaged in the western part of Operation Cartwheel, the encircling and neutralisation of the Japanese base at Rabaul in New Britain. After this operation was completed, I Corps took part in prolonged Allied mopping-up operations along the northern shores of New Guinea.

In by far the largest series of operations in the theater during the war, I Corps took part in the invasion of Luzon. It was still engaged on mopping up operations there at the end of the war.

After the end of hostilities, I Corps was inactivated.

Current Order of Battle

The current order of battle of I Corps is somewhat muddy.

1st Air Support Operations Group

1st Weather Squadron

1st Military Police Brigade

1st Personnel Group

9th Finance Battalion

22nd Personnel Services Battalion

142nd Signal Brigade

29th Signal Battalion

62nd Medical Brigade

201st Military Intelligence Brigade

502nd Military Intelligence Battalion

304th Support Center (Rear)

555th Engineer Group

14th Engineer Battalion

864th Engineer Battalion

593rd Corps Support Group

44th Corps Support Battalion

57th Transportation Battalion

80th Ordnance Battalion

Likely Subordinate Units

3rd Brigade, 2nd Infantry Division "Arrowhead Brigade"

1st Battalion, 23rd Infantry "Tomahawks"

2nd Battalion, 3rd Infantry

5th Battalion, 20th Infantry

1st Squadron, 14th Cavalry

1st Battalion, 37th Field Artillery*

296th Forward Support Battalion*

C Company, 5th Battery, 5th Air Defense Artillery Battalion

334th Signal Company

18th Engineer Company

209th Military Intelligence Company

C Company, 52nd Anti-Tank Company

*These units are technically under divisional command, and are arbitrarily assigned to brigades

1st Brigade, 25th Infantry Division "Lancers"

1st Battalion, 5th Infantry "Bobcats"

1st Battalion, 24th Infantry "Deuce Four"

2nd Squadron, 14th Cavalry

2nd Battalion, 8th Field Artillery "Automatic"

25th Forward Support Battalion

A Company, 65th Engineers (Sapper)

C Company, 62nd Air Defense Artillery

Likely Subordinate National Guard/Reserve Units

40th Infantry Division (Mechanized) (California Army National Guard)

I Corps Artillery (Utah National Guard)

29th Infantry Brigade (Separate) (Hawaii National Guard)

81st Armor Brigade (Separate) (Washington National Guard)

116th Armored Cavalry Brigade (Idaho National Guard)

207th Infantry Group (Scout) (Alaska National Guard)

278th Armored Cavalry Regiment (Tennessee National Guard)

66th Aviation Brigade (CBT) (Corps) (Washington National Guard)

111th Air Defense Artillery Brigade (New Mexico National Guard)

35th Engineer Brigade (Missouri National Guard)

177th Military Police Brigade (Michigan National Guard)

142nd Signal Brigade "Voice of America's Corps" (Alabama National Guard)

364th Civil Affairs Brigade (Airborne) (Reserve)

464th Chemical Brigade (Reserve)

326th Corps Finance Group (Reserve)

82nd Rear Operations Company (Oregon National Guard)

External links

• I Corps Home Page - official site.
• GlobalSecurity.org: I Corps