I Corps - "America's Corps"
Designated an early deploying corps for military contingencies in the Pacific, I Corps [First Corps] is able to deploy on short notice with both Active Army and Reserve Component forces. I Corps is a contingency force with active, reserve and national guard units in 47 out of 50 states. One brigade out of the I Corps forces, usually drawn from the 25th Infantry Division or 172nd Infantry Brigade, is assigned as the "Division Ready Brigade" for Pacific contigencies, and is available within 48 hours of alert by air transport.
I Corps is unique among the three continental United States (CONUS) Corps in that it has no assigned active Army divisions in peacetime and is composed of a balance of Active and Reserve base units in peacetime and wartime. It is further unique in that it is under the Combatant Command of U.S. Pacific Command and under the Operational Control of U.S. Army Pacific. As it is CONUS-based, it relies on U.S. Army Forces Command for Title 10 U.S. Code support, or in Joint terminology, is Administratively Controlled (ADCON) to Forces Command.
War plans for I Corps include the Defense of Korea or the Defense of Japan. As a U.S. PACOM major operational headquarters, I Corps is designated by CINCPAC as a standing Joint Task Force (JTF) for theater-wide contingencies. The other primary PACOM standing JTF's are 7th Fleet in Yokosuka, Japan, and III MEF in Okinawa, Japan. Thus, I Corps' readiness responsibilities range from conventional Corps roles in a medium-intensity conflict to a full spectrum of missions as a USPACOM JTF.
I Corps base units include approximately 20,000 active-duty soldiers at Fort Lewis, Washington, and an equal number of U.S. Army Reserve and National Guard soldiers based in many of the fifty states. Thus I Corps' name, "America's Corps!" While I Corps is not directly responsible for the readiness of the RC units, it does coordinate with the U.S. Army Reserve Command and the states' Adjutant Generals to articulate the wartime requirements and anticipated missions for these Corps base units.
Many of these Reserve Component units participate in I Corps' exercises in CONUS and overseas, including exercises in Japan and Thailand. I Corps' Reserve Component units participated in Operations Joint Guard and Able Sentry. I Corps is at the forefront of the integration of Active Component and Reserve Component units. The military intelligence brigade and engineer group each contain organic Reserve Component subordinate units. It is one of two organizations in America's Army sponsoring the Integrated Infantry Battalion Experiment which will test the ability of integrated Active Component and Reserve Component combat arms units to train and deploy on operational missions. I Corps also works hard to maintain good relationships with the geographically proximate Pacific Northwest enhanced separate brigades from Washington and Oregon.
I Corps serves as AC associate/senior mentor and retains responsibilities for the following corps base units: 311th CS COSCOM, HHC; 35th EN Bde, HHC; I Corps Artillery, HHC; 66th AV Brigade, HHC; 142d SC Brigade, HHC; 464th CM Brigade, HHC; 326th FI Group, HHC; 82d HQ Detachment, RTOC; 177th MP Brigade, HHC; 364th CA Brigade, HHC; and 426th MD Brigade, HHC.
Under a new concept called "corps packaging," all of the National Guard's eight combat divisions and 15 enhanced separate brigades will be matched with active-component divisions at the corps level. Army Chief of Staff Gen. Eric K. Shinseki announced this expansion of teaming between active and Guard divisions 14 September 2000 in a speech to the National Guard Association annual conference in Atlantic City, NJ. Under I Corps at Fort Lewis, Wash., California's 40th Infantry Division (Mechanized) is teamed with the Army's 2nd Infantry Division in Korea, while the Corps also includes three of the Guard's enchanced brigades -- the 116th Armored Cavalry Brigade in Idaho, the 29th Infantry Brigade in Hawaii, and Washington's 81st Infantry Brigade.
The Total Army Analysis [TAA] is a biennial, multiphased force-structuring process that generates the tactical support forces and general purpose forces necessary to support divisional and non-divisional combat forces in executing the national strategy, given resource constraints and end-strength guidance.
The TAA-05 confirmed the 111th ADA Brigade missioning to I Corps.
I Corps was activated at Neufchateau, France, 15 January 1918. In July it helped stop a German drive, and counterattacked in the Aisne-Marne offensive. The Corps attacked the southern face of the St. Mihiel Salient in September and carried all its objectives. I Crops was transferred to the Meuse-Argonne front on 20 September where it took part in the last major offensive of the war, fighting through the Argonne Forest. I Corps was demobilized at Tonnerre, France, in March 1919.
On 1 November 1940, I Corps was reactivated. It moved to Australia in August 1942 where it prepared for action in New Guinea. During the fall and winter of 1942, I Corps fought in the Buna-Gona battles on New Guinea. In April 1944, an I Corps task force made an amphibious assault at Hollandia. When the campaign ended, the 18th Japanese Army had been isolated. By 24 June, I Corps units had secured the Island of Biak off the New Guinea Coast. With new Guinea secure, attention turned to the Philippines.
I Corps was next assigned an amphibious landing on Luzon. It landed at Lingayen Gulf and, in a month-long advance, pushed across the island to split the Japanese forces. The Corps then turned north and drove two hundred miles to break the Japanese hold on northern Luzon. A war's end, the Corps was preparing to lead an assault in the invasion of Japan.
After the surrender in 1945, the mission became one of occupation of Japan. I Corps remained in Japan until 1950 when it was inactivated.
The Korean War broke out three months later. On 2 August 1950, I Corps was reactivated, and by 27 August the Corps had assumed command of units in the Pusan Perimeter. I Corps led an offensive launched from the perimeter. By 1 October, the Corps had driven past Seoul and beyond the 38th Parallel. On the 29th it took the North Korean Capital, and by month's end the Corps was only a few miles from the border to China.
The Chinese entered the War, forcing all UN Forces to withdraw. They re-took Seoul and pushed on south in late 1950. I Corps counterattacked and participated in the see-saw battles that swept back and forth around the 38th Parallel for the next year. Periods of relative quiet and heavy fighting continued at such places as Pork Chop Hill, Old Baldy, and The Hook for the next two years, until the Armistice was signed.
After the Armistice in 1953, Republic of Korea assumed the responsibility of the defense of the eastern half of the Demilitarized Zone (DMZ) in the form of First Republic of Korea Army (FROKA). Western half of the DMZ was defended by the United States First Corps Group. In 1971, under Nixon's détente policy, US Seventh Infantry Division was withdrawn, leaving the US Second Infantry Division as the only US Army unit in Korea. I Corps remained in Korea as a two-division formation until until 1971 when the Corps Headquarters was reduced to zero strength. With growing confidence among Korean senior staff and American insistance on burden-sharing, a new command was formed to defend the western half of DMZ. By 1982, the Third Republic of Korea Army (TROKA) assumed command of the Republic of Korea Corps formerly under US First Corps Group.
In each of the three wars there is a striking similarity: In each the Corps entered the fighting when things were going badly, and in each the Corps performed its mission, emerging victorious. It has participated in more campaigns than any other corps and is the only corps ever to receive the U.S. Presidential Unit Citation. First Corps is the most decorated corps in the active Army.
I Corps was transferred to Fort Lewis, Washington, on 1 October 1981, where it was brought back to strength and re-organized as a quick reaction or "contingency" corps for Pacific theatre units.
For the Active Component and Reserve Component (AC-RC) to truly share responsibility, The Army established some cross-component general officer and command/staff billets. The Deputy Commanding General of I Corps, one of the Army's three active corps, is an RC general officer. I Corps, headquartered at Fort Lewis, Washington, has subordinate units throughout the continental United States. Almost 80 percent of its units are in the RC. Assigning an RC deputy commander fosters integration and improved command and control. The Army is reviewing other general officer positions for designation as RC billets.
