I Corps ( United States ) I Corps " America ' s Corps " is a corps of the United States Army headquartered in Joint Base Lewis - McChord , Washington . It is a major formation of United States Army Forces Command . I Corps ' current mission is part of the United States ' Asia - Pacific Shift . The Pacific Rim Rebalance will involve several combined and joint military exercises in Japan , Korea , Thailand , Philippines , and Australia . Part of I Corps ' objectives for these exercises will be Joint Task Force certification in support of United States Pacific Command missions . Activated in World War I in France , I Corps oversaw US Army divisions as they repelled several major German offensives and led them into Germany . The corps was deactivated following the end of the war . Reactivated for service in World War II , the corps took command of divisions in the south Pacific , leading US and Australian forces as they pushed the Japanese army out of New Guinea . It went on to be one of the principal leading elements in the Battle of Luzon , liberating the Philippines . It then took charge as one of the commanding headquarters in the occupation of Japan . Deployed to Korea at the start of the Korean War , the corps was one of three corps that remained in the country for the entire conflict , commanding US , British , and South Korean forces through three years of back - and - forth campaigns against North Korean and Chinese forces . Following the end of the war , it remained in Korea for almost 20 years guarding the Korean Demilitarized Zone . Active today , the corps acts as a subordinate headquarters of United States Army Forces Command , and has also seen deployments in support of Operation Iraqi Freedom and Operation Enduring Freedom . History . World War I . Following the American declaration of war on Germany , on 6 April 1917 , I Corps was organized and activated on 15 – 20 January 1918 , in the National Army in Neufchâteau , France , the first of several corps - sized formations intended to command divisions of the American Expeditionary Force in Europe during World War I . Assisted by the French XXXII Corps , the headquarters was organized and trained ; on 20 January , Major General Hunter Liggett took command . In February , the corps consisted of the 1st , 2nd , 26th , 32nd , 41st , and 42nd Infantry Divisions . From February to July , 1918 , the German Army launched four major offensive s , attempting to secure victory before the full American forces could be mobilized . The final offensive , started in July 1918 , was an attempt to cross the Marne , in the area of Château - Thierry , but I Corps and other formations on the American lines held , and the attack was rebuffed . With the defeat of these German drives , I Corps conducted its first offensive mission , participating in the Second Battle of the Marne from 18 July until 6 August , which resulted in the reduction of the more important salients driven into Allied lines by the German offensives . After a brief period in the defensive sectors of Champagne and Lorraine between 7 August and 11 September , the corps took part in the St . Mihiel attack on 12 September , which reduced the German salient there during the next four days . Then followed another period on the defense in Lorraine as preparations advanced for what was to be the final Allied offensive of the war . On 26 September , I Corps troops began the attack northward that opened the Meuse - Argonne Offensive . From that day until 11 November 1918 when the war ended , I Corps was constantly moving forward . The I Corps shoulder sleeve insignia was first worn by members of I Corps after approval from the AEF on 3 December 1918 , but it was not officially approved until 1922 . I Corps continued to train in France , until it was demobilized on 25 March 1919 . During its time in World War I , I Corps commanded the 1st , 2d , 3d , 4th , 5th , 6th , 26th , 28th , 32d , 35th , 36th , 41st , 43d , 77th , 78th , 80th , 82d , 90th , 91st , 92d Infantry Divisions at one point or another . Also assigned to the corps were the French 62nd , 167th and 5th Cavalry Divisions . Interwar Period Established in the US Army on 20 August 1920 with headquarters at Army Base , Boston , and organized from the discontinued Northeastern Department . The First Corps Area included the states of Maine , New Hampshire , Vermont , Massachusetts , Connecticut , and Rhode Island . For administrative purposes and tactical control in connection with the coast defenses and field operations incident thereto , that part of the state of New York that lies east of west longitude 72 degrees , 30 minutes ( which included Forts Terry and H . G . Wright , NY ) was attached to the First Corps Area . HQ , First Corps Area was responsible for the mobilization , administration , and training of units of the First and Fourth Armies , I and XI Army Corps , coast defense units of the First C . A . District , select units of the GHQR , and the Z . I . support units of the First CASC . Mobile units of the corps area , less harbor defense , GHQR , and Z . I . units , were originally assigned to the First and Fourth Armies from 1921 to 1933 . The coast defense units in the corps area were assigned to the various harbor defense commands of the First Coast Artillery District . The First Corps Area Training Center was established in 1921 with headquarters at Army Base , Boston , to train R . A . and O . R . units , as well as ROTC cadets and CMTC candidates . Originally , the training was to be accomplished at Camp Devens , MA , for all arms and services , except cavalry and field artillery , which were to train at Fort Ethan Allen , VT . With the inactivation of the First Corps Area Training Center in 1922 , Camp Devens became the primary training center for corps area infantry units only . Air corps units were sent to Mitchel Field , NY ; engineer units were sent to Fort Du Pont , DE ; and signal corps units were sent to Camp Alfred Vail ( later renamed Fort Monmouth ) , NJ . Corps area maneuvers of R . A . mobile units were held , those years when funds were available , near Fort Ethan Allen . With the adoption of the four field army plan on 1 October 1933 , the mobile units of the First Corps Area were reassigned to the First Army or GHQR , or were demobilized . For the administration of O . R . units , all organizations initially came under the control of the I Corps , or the 76th , 94th , and 97th Divisions . When the XI Corps was inactivated in 1925 , the HQ , Non - Divisional Group was established to direct the organization , training , and administration of all nondivisional units . This arrangement was short - lived . On 8 September 1925 , the Non - Divisional Group was discontinued and the HQ , Artillery Group was established . This new group managed only the corps area nondivisional field artillery units , the 158th Cavalry Brigade , and personnel assigned to the I and XI Corps . The rest of the nondivisional units were turned over to the three O . R . divisions for administrative control . The corps area was reorganized into three “ military areas ” on 19 August 1938 . At that time , the 1st Military Area assumed control of the 97th Division area ( Maine , New Hampshire , and Vermont ) , the 2d Military Area assumed control of the 94th Division area ( Massachusetts ) , and the 3d Military Area assumed control of the 76th Division area ( Rhode Island and Connecticut ) . The First Corps Area began assigning Reserve personnel to CASC units as early as 1925 . At that time , the corps area originally referred to the CASC units as “ Z . I . installation units ” in mobilization plans and other documents . The HQ , First Corps Area actually began functioning as a service command headquarters in October 1940 and was redesignated HQ , First CASC in May 1941 . It was further redesignated HQ , First Service Command on 22 July 1942 . In July 1921 , Headquarters , I Corps was Reconstituted in the Organized Reserves to support the six - army plan called for by the mobilization plans developed in 1920 – 21 . Each field army was to consist of three corps . For some unknown reason , I Corps was reconstituted in the Organized Reserves even though it was to consist primarily of Regular Army and National Guard units . Another anomaly was that I Corps was newly constituted and bore no connection to previously existing units . The designation of I Corps was related to the corps area designation . For example , the First Corps Area was allotted the I and XI Corps . By the end of 1922 , I Corps had been organized . Headquarters , I Corps wasn ’ t allotted a commanding general , and it is unlikely that I Corps was ever more than 50 percent complete in terms of their authorized officer strength and far less than that in regard to enlisted reservists . I Corps headquarters was partially activated during 1921 – 22 to function as the administrative headquarters for Organized Reserve non - divisional units ( less coast artillery units ) . I Corps headquarters were largely organized with Reserve personnel , but possessed a small Regular Army staff to carry out the headquarters administrative duties concerning the Organized Reserve units under its control . The R . A . staff was organized as follows : Corps Staff : Chief of Staff colonel Adjutant General / G1 ( Lieutenant Colonel Assistant Chief of Staff , General Staff G3 Lieutenant Ccolonel Assistant Chief of Staff , General Staff G3 Major Senior Noncommissioned Officer ( NCO ) Staff Sergeant Administrative Sergeant Sergeant Enlisted Clerk Corporal Enlisted Clerk / Driver Private By 1925 , this headquarters was inactivated due to budget constraints and congressional pressure to eliminate them , but remained organized with Reserve personnel . The functions of the corps headquarters , were taken over by two new commands designated as the Non - Divisional Group and the Artillery Group . Like their higher headquarters , the field armies , the interwar corps were “ type ” organizations . They consisted of a standard set of subordinate units necessary for wartime missions . World War II . On 15 August 1927 , XX Corps was reconstituted in the Regular Army . Two months later , on 13 October 1927 , the XX Corps was redesignated as I Corps . However , the corps headquarters remained inactive during peacetime , until the US Army ' s buildup following the outbreak of War in Europe . On 1 November 1940 , I Corps was reactivated at Columbia , South Carolina . For the next nine months , the corps supervised training and large scale divisional maneuvers . In early March 1942 Major General George Patton , commander of the U . S . First Corps and his staff surveyed the Mojave Desert for possible large scale training . Patton had been ordered by the War Department to locate , establish and command a training center to train troops for desert warfare . Army rationale was that American forces soon would be required to fight the German enemy in North Africa . New Guinea Campaign . On 6 July 1942 Lieutenant General Robert L . Eichelberger took command of the corps which he would lead through the majority of its service in the war . In the summer of 1942 the corps was ordered to Australia , closing into the area at Rockhampton on 17 October 1942 . This move was to be part of a larger overall offensive in the south Pacific region . The corps at this time comprised the 41st and 32nd Divisions , engaged in the defense of British New Guinea , the beginning of the New Guinea campaign . Though the Japanese advanced rapidly at first , a number of factors slowed their progress against the Allied forces . Stubborn resistance from two Australian brigades bought time for I Corps reinforcements to arrive while the terrain proved more difficult than the Japanese had anticipated . Supplies , which were already insufficient for the Japanese forces , were shortened even more as Japan ' s high command diverted them to the Guadalcanal campaign . The Japanese attack stalled , and once the threat of a Japanese invasion of Australia was abated , I Corps launched an offensive to push back the Japanese . With the 32nd Division and the 163rd Infantry Regiment of the 41st Division , the offensive was launched across the Owen Stanley Mountains of New Guinea . This force , later augmented by the Australian 7th Division , fought the Battle of Buna - Gona , slowly advancing north against a tenacious enemy under harsh weather and terrain conditions . Overstretched Japanese forces , low on supplies , were eventually overcome by US and Australian forces . Despite being surrounded , trapped , and outnumbered , the Japanese forces continued to fight until they were completely wiped out by Allied forces . Buna , on the north coast of the island , fell on 22 January 1943 . The campaign was the first major Allied victory against the Japanese Army , and I Corps received the Presidential Unit Citation . This victory marked the turn of the tide in the ground war against Japan . After this campaign I Corps returned to Rockhampton , where it was engaged in the training of the Allied forces beginning to arrive in that area for the coming campaigns . From February 1942 until March 1943 I Corps prepared for its next assignment , Operation Cartwheel . That mission was the capture of Hollandia on the north coast of Dutch New Guinea ; the units allocated to the corps for this task were the 24th and 41st Infantry Divisions . The Task Force established itself ashore after a successful amphibious assault on 19 April 1944 . It then began an offensive in that area to remove Japanese forces , before establishing air bases there . The battle was a vicious one ; the jungles and swamps made difficult fighting ground , and it was not until 6 June that the area was secured . The entire Japanese 18th Army was cut off from its bases by the force . Following this campaign the corps directed the seizure of the island of Biak , which was secured by 24 June , to complete the advances necessary for the subsequent invasion of the Philippine Islands . On 20 August Major General Innis P . Swift succeeded General Eichelberger as commander of the corps . Luzon . The corps was assigned to the Sixth United States Army in preparation for the offensive in the Philippines from the assets of the Philippine Commonwealth Army , Philippine Constabulary and the recognized guerrilla units . On 9 January 1945 , I Corps successfully landed on the coast of the Lingayen Gulf in Northern Luzon with the mission of establishing a base for future operations to the north and of denying the enemy northern access to the South China Sea . As a part of the Sixth Army with an overall force of 175 , 000 men , the American forces faced over 260 , 000 Japanese in Luzon . In a sustained drive of thirty - four days which covered over 100 miles , I Corps crossed central Luzon and thus separated the Japanese forces in the north from those in southern Luzon , destroying Japanese armored units along the way . Additional landings at Samar and Palawan were conducted in February , reducing the pressure on the forces of I Corps . Following this accomplishment , the corps turned northward and began the systematic reduction of the enemy positions on the approach to the Cagayan Valley . The breakthrough into the valley was followed by a swift exploitation that took the corps to the north coast . This advance covered two hundred miles in little over 100 days ; eliminating effective enemy resistance in northern Luzon . Manila was recaptured by the Allies after heavy fighting that ravaged the city . The intense fighting that ensued cost 8 , 000 killed and 30 , 000 wounded in the Sixth Army , compared to 190 , 000 dead for Japan . As the Sixth Army finished off the Japanese on Luzon , the Eighth United States Army in the south sent units all throughout the Philippines to eliminate remaining Japanese resistance on the islands . The Tenth United States Army in the north commenced securing Okinawa and Iwo Jima . With the defeat of the Japanese at each of these places , the US forces had locations from which to launch attacks into mainland Japan . Allied forces then began preparing for the invasion of mainland Japan , Operation Downfall . I Corps was assigned as one of four Corps under the command of the Sixth Army , with a strength of 14 divisions . I Corps was to lead the assault on Miyazaki , in southern Kyūshū , with the 25th , 33rd , and 41st Infantry Divisions . Opposing them would be the Japanese 57th Army , with the 154th , 156th , and 212th Japanese Infantry Divisions . Before the assault could be launched , Japan surrendered , following the use of nuclear weapons on Hiroshima and Nagasaki . During World War II , the 6th , 8th , 9th , 24th , 25th , 30th ( during training in U . S . only ? ) , 32nd , 33rd , 37th , 41st , 43rd , 77th and 98th Infantry Division s were assigned to I Corps at one time or another , along with the 2nd Marine Division , 7th Australian Division , and elements of the 11th Airborne Division . Occupation of Japan . After the end of hostilities , I Corps was assigned to occupation duty in Japan . On 19 September 1945 the corps , with the assigned 33rd Infantry Division , sailed from Lingayen Gulf for Japan , landing on the island of Honshū on 25 September , three weeks after Japan ' s formal surrender . The next few years were a period during which the terms of the surrender were supervised and enforced ; Japanese military installations and material were seized , troops were disarmed and discharged , and weapons of warfare disposed of . The duties of the occupation force included conversion of industry , repatriation of foreign nationals , and supervision of the complex features of all phases of Japanese government , economics , education , and industry . By 1948 , as the purely occupational mission was accomplished , troops of the corps focused more military training and field exercises designed to prepare them for combat . Its force was eventually downsized to the 24th Infantry Division on Kyūshū and 25th Infantry Division on mid - Honshū . The US Army continued a slow and steady process of post - war drawdown and demobilization on its own , and on 28 March 1950 , the corps was formally inactivated in Japan , and its command consolidated with other units . Korean War . Only a few months later , the Korean War began , and units from Japan began streaming into South Korea . The Eighth United States Army , taking charge of the conflict , requested the activation of three corps headquarters for its growing command of U . N . forces . I Corps was reactivated at Fort Bragg , North Carolina , on 2 August 1950 . Pusan Perimeter . Advance elements of the headquarters took their place in the Pusan perimeter on 27 August . The headquarters , designated " Task Force Jackson " , assumed control of the South Korean I Corps , the 21st Regimental Combat Team , and the 3rd Battalion Combat Team of the 9th Infantry Regiment . On 12 September , under command of Lieutenant General Frank W . Milburn , the corps became operational . It took command of the 1st Cavalry Division , 24th Infantry Division , and South Korean 1st Infantry Division , along with the 27th British Commonwealth Brigade , defending the Naktong River area against attacking North Korean units . Amphibious landings at Inchon by X Corps hit North Korean forces from behind , allowing I Corps and IX Corps to break out of Pusan . Four days later I Corps troops pushed northward against crumbling enemy opposition to establish contact with forces of the 7th Infantry Division driving southward from the beachhead . Major elements of the North Korean Army were destroyed and cut off in this aggressive penetration ; the link - up was effected south of Suwon on 26 September . The offensive was continued northwards , past Seoul , and across the 38th Parallel on 1 October . The momentum of the attack was maintained , and the race to the North Korean capitol , Pyongyang , ended on 19 October when elements of the South Korean 1st Infantry Division and U . S . 1st Cavalry Division both entered the city . The advance continued , but against unexpectedly stiffening enemy resistance . On 25 October the first Chinese prisoners on the Eighth Army front were taken by I Corps troops . By the end of October the city of Chongju , forty miles from the Yalu River border of North Korea , had been captured . Chinese Intervention . On 27 November , China entered the war on the side of North Korea against the UN . Massed Chinese attacks were immediately launched against troops of the corps . The Eighth Army suffered heavy casualties , ordering a complete withdraw to the Imjin River , south of the 38th parallel , having been devastated by the overwhelming Chinese force . In the wake of the retreat , the disorganized Eighth Army regrouped and re - formed . I Corps relinquished command of the 1st Cavalry Division , the 24th Infantry Division , and the 27th British Brigade , taking command of the 3rd Infantry Division and the 25th Infantry Division in their place . On 1 January 1951 , 500 , 000 Chinese troops attacked the Eighth Army ' s line at the Imjin River , forcing them back 50 miles and allowing the Chinese to capture Seoul . The Chinese eventually advanced too far for their supply lines to adequately support them , and their attack stalled . The Eighth Army , battered by the Chinese assault , began to prepare spring offensives to retake lost ground . Following the establishment of defenses south of the capital city , General Matthew B . Ridgway ordered I , IX , and X Corps to conduct a general counteroffensive against the Chinese forces , Operation Thunderbolt . Between February and March , the corps participated in Operation Killer , pushing Chinese forces north of the Han River . This operation was quickly followed up with Operation Ripper , which retook Seoul in March . After this , Operations Rugged and Dauntless in April saw Eighth Army forces advance north of the 38th parallel and reestablish themselves along the Kansas Line and Utah Line , respectively . As I Corps troops approached the Iron Triangle formed by the cities of Chorwon , Kumhwa , and Pyongyang , Chinese resistance increased . By that time , the 1st South Korean Infantry Division was relieved from the corps and assigned to one of the Korean corps . The 1st Cavalry Division was returned to the corps in its place . In late April , the Chinese launched a major counterattack . Though the 24th and 25th Infantry Divisions were able to hold their ground against the Chinese 9th Chinese People ' s Volunteers ( CPV ) Army Corps , the South Korean 6th Infantry Division , to the east , was destroyed by the 13th CPV Army Corps , which penetrated the line and threatened to encircle the American divisions . The 1st Marine Division and 27th British Commonwealth Brigade were able to drive the 13th Army Corps back while the 24th and 25th Divisions withdrew on 25 April . The line was pushed back to Seoul but managed to hold . Stalemate . In September , the UN Forces launched another counteroffensive with the 24th Infantry Division at the center of the line , west of the Hwachon Reservoir . Flanked by the South Korean 2nd and 6th Divisions , the 24th advanced past Kumwha , engaging the 20th and 27th CPV Armies . In November , the Chinese attempted to counter this attack , but were unsuccessful . It was at this point , after several successive counteroffensives that saw both sides fighting intensely over the same ground , that the two sides started serious peace negotiations . In late 1951 , the 1st Cavalry Division , depleted after having suffered 16 , 000 casualties so far in the conflict , was relegated to the Far East reserve to rebuild . It was replaced by the 45th Infantry Division of the Oklahoma Army National Guard , which was newly arrived in the theater . In March 1952 , the corps grew in size as the 25th Infantry Division was relieved from its command and it gained command of 1st British Commonwealth Division and the South Korean 1st Division , 8th Division , and 9th Divisions . In June 1952 , a ten - day attack against 45th Infantry Division outposts was repulsed . September 1952 began with renewed enemy attacks against the outposts that protected the main line . Enemy attacks up to regimental size against garrisons of platoon and company strength were turned back by Corps troops . Outposts at Bunker Hill , The Hook , Kelly , Old Baldy Hill , Nori , and Pork Chop Hill were defended in heavy fighting within I Corps ' area of responsibility . All along the front , the enemy was driven back with thousands of casualties . In January 1953 , the corps underwent its last major reorganization of the war , losing command of the US 3rd , 24th , and 45th Infantry Divisions , the South Korean 8th and 9th Infantry Divisions , and the British 1st Commonwealth Division , while taking command of the US 2nd , 7th , and 25th Infantry Divisions and the 1st Marine Division . On 23 January 1953 , the first major action of the year was initiated with a raid by aggressive infantrymen of the South Korean 1st Infantry Division against the enemy ' s Big Nori positions . The next months saw many such raids which harassed the enemy , captured prisoners , and destroyed defensive works . Beginning in March , the Communists continually attacked the corps outposts . In that month , troops on Old Baldy were withdrawn , on orders from I Corps , after suffering heavy casualties from the Chinese . On 10 April 1953 Lieutenant General Bruce C . Clarke , who was to see the corps through the remainder of its combat , assumed command . The fighting on the outposts continued ; the 7th Infantry Division stopped wave after wave of troops that the Chinese threw against Pork Chop Hill . Troops of the Turkish Brigade , attached to the 25th Infantry Division , defended Outposts Berlin , Vegas , Carson , and Elko in fierce hand - to - hand combat . They were ordered to evacuate all but the Berlin position at the end of May . The 1st British Commonwealth Division ejected the Chinese after their assault on the Hook . The 1st ROK Division troops were ordered off the positions on Queen , Bak , and Hill 179 when heavy enemy assaults divested them of their tactical value . The closing days of the fighting saw the 7th Infantry Division withdrawn from Pork Chop and the 1st Marine Division ordered to evacuate the Berlin positions for the same reason . Cold War . After the 1953 armistice , the defense of the Korean Demilitarized Zone was handled by the South Korean and American armies . The eastern half of the border was handled by the South Korean Army while I Corps took charge in the west . For the next 18 years , the corps oversaw US forces on the DMZ , seeing only occasional incidents with the North Korean army . In 1971 , under Nixon ' s détente policy , the 7th Infantry Division was withdrawn , leaving the 2nd Infantry Division as the only US Army unit in Korea . I Corps remained in Korea as a two - division formation until 1971 when it was reduced to zero strength and was replaced in 1982 by the Third Republic of Korea Army ( TROKA ) . In 1980 , Fort Lewis , Washington was notified of a major change of structure . A corps headquarters was to be activated in March 1982 . I Corps was formally activated on 1 October 1981 , much earlier than expected . On 1 August 1983 , the corps expanded its operational control of active Army units outside Fort Lewis , to include the 7th Infantry Division at Fort Ord , California , and the 172nd Infantry Brigade in Alaska , which then became part of the 6th Infantry Division . In 1988 , the distinctive unit insignia was approved for the corps . This was the fourth design held by the corps , with previous versions being approved then retracted in 1942 , 1970 , and 1982 . Gulf War . Following the end of the Cold War in 1989 , the US government conducted careful restructuring of national priorities and of the defense establishment . Fort Lewis , ideally located to act as a base for mobilization and power projection into the Pacific region , was one of few military bases that did not downsize with the US military overall . Thus , while most of the Army was downsizing , Fort Lewis began to grow , however , several tenant units such as the 9th Infantry Division were downsized . The 3rd Brigade , 9th Infantry Division became the 199th Infantry Brigade , attached to I Corps , remaining under I Corps until its redesignation as the 2nd Armored Cavalry Regiment , and its departure for Fort Polk , Louisiana in 1993 . Also in 1990 , the U . S . intervened in the Middle East with Operation Desert Storm . During that intervention , Fort Lewis deployed 34 active and 25 reserve component units to Saudi Arabia . I Corps also contributed to the command structure , with the I Corps Commander , LTG Calvin A . H . Waller and the Deputy I Corps Commander , MG Paul R . Schwartz , assisting General H . Norman Schwarzkopf , the Commander of the American Forces . I Corps expanded its contingency missions and became a quick - response corps . For several months , I Corps was the nation ' s worldwide contingency corps , while the XVIII Airborne Corps was engaged in the Gulf War . This caused a good deal of activity on Fort Lewis , as the post restructured itself to support the corps ' new mission , and to insure that it had a smooth , rapid departure in case they were needed anywhere in the world . This duty was returned to XVIII Airborne Corps upon its return to the United States . The corps then began to convert to a permanently structured , no - mobilization contingency corps and was placed under the operational control of the United States Army Forces Command . This entailed the addition of a number of active component corps units . In preparation for these new requirements , Fort Lewis began to receive new corps support units which were coming out of Europe . One of these was the 7th Engineer Brigade which was inactivated on 16 January 1992 and immediately reactivated as the 555th Engineer Group . On 16 February 1992 the 210th Field Artillery Brigade , also from Europe , was activated . In 1997 , the 35th Air Defense Artillery Brigade moved to Fort Bliss , Texas , to join other air defense brigades . The corps and Fort Lewis would see a reshuffling of units in and out of the area through 2000 . Plans were drawn up for emergency operations for I Corps should a major conflict emerge in the Pacific region . Plans exist for I Corps to rapidly deploy in defense of Japan or South Korea . War on Terrorism . With the events of 11 September 2001 , I Corps began providing support for Army units deploying in support of the War on Terrorism . Its assets were active in providing combat support and combat service support missions , including Operation Enduring Freedom in Afghanistan , Operation Iraqi Freedom in Iraq and the domestic Operation Noble Eagle . On 4 February 2004 , I Corps forward headquarters deployed to Iraq . The element , called Task Force Olympia , deployed to Mosul , Iraq in January 2004 , where it assumed its mission from the 101st Airborne Division to form a headquarters to exercise command and control of all coalition and Iraqi forces in northern Iraq . It coordinated the efforts of both of the active Stryker Brigade Combat Team s , attached engineers , civil affairs , signal , and other supporting units as well as Iraqi security forces , eventually numbering more than 12 , 000 . The Iraqi security forces included four Civil Defense Corps battalions , three Border Police battalions , several thousand members of the Iraq Facility Protection Security Forces and an Armed Forces battalion . After more than a year in Iraq , the corps forward headquarters handed over responsibility for northern Iraq to the soldiers of Task Force Freedom and 11th Armored Cavalry Regiment in February 2005 . In 2008 , it was announced that I Corps was to deploy to Iraq in 2009 , to replace XVIII Airborne Corps in support of Operation Iraqi Freedom . Soldiers of the corps trained for a year in preparation for the deployment , which began on 9 April 2009 . I Corps filled the role of Multi - National Corps - Iraq at Al - Faw Palace . In January 2010 , Multi - National Corps - Iraq integrated with Multi - National Forces - Iraq ( MNF - I ) and Multi - National Security Transition Command – Iraq ( MNSTC - I ) to form United States Forces - Iraq ( USF - I ) . Over its one year deployment , the corps oversaw the responsible drawdown of major components of US Forces in Iraq . I corps returned from Iraq in March 2010 following their RIP / TOA with III Corps . OEF . I Corps headquarters deployed to Afghanistan to serve as the headquarters of the International Security Assistance Force Joint Command ( IJC ) for a period of one year . The commander of I Corps , LTG Scaparrotti , served concurrently as the commander of the International Security Assistance Force Joint Command and Deputy Commander , U . S . Forces – Afghanistan from July 11 , 2011 to July 11 , 2012 . Asia - Pacific Shift . I Corps shifted its mission to the Asia - Pacific region in mid - 2012 . I Corps Commander Lt . Gen . Robert Brown announced this Pacific Rim rebalance during his Change - of - Command Ceremony at Joint Base Lewis - McChord . In late 2011 , President Barack Obama and Secretary of Defense Leon Panetta signaled the Asia - Pacific pivot and have made several trips to the region . Organization . I Corps is unique among the active US Army corps in that it is composed of a mixture of active duty and US Army Reserve units in 47 of the 50 U . S . States , for a total of around 20 , 000 active duty and 20 , 000 army reserve forces . Honors . The I Corps was awarded seven campaign streamer s for service in World War I , three campaign streamers and two unit decoration s in World War II , ten campaign streamers and one unit decoration in the Korean War , one unit award during Operation Iraqi Freedom , and one unit award in peacetime , for a total of 20 campaign streamers and five unit decorations in its operational history .