I Corps was created July 24, 1950, just before the Battle of Pusan Perimeter

Battle of Pusan Perimeter

The Battle of Pusan Perimeter was a large-scale battle between United Nations and North Korean forces lasting from August 4 – September 18, 1950. It was one of the first major engagements of the Korean War...

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I Corps consisted of the 8th Infantry Division

8th Infantry Division (South Korea)

The 8th Infantry Division was a military formation of the Republic of Korea Army during the 20th Century.-History:The unit comprises the 10th, 16th and 21st Regiments. The 16th Infantry Regiment was originally activated as the 16th Regiment on October 28, 1948 at Masan and was first commanded by...

 and the Capital Division

Capital Division (South Korea)

The Capital Mechanized Infantry Division , also known as Tiger Division , is currently one of the five mechanized infantry divisions in the Republic of Korea Army...

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During the battle of the Pusan Perimeter (July-September, 1950), its headquarters was at Sangju

Sangju

Sangju is a city in North Gyeongsang Province, South Korea. Although Sangju is rather rural, it is very old and was once a key city. Along with Gyeongju, it gives rise to half of the name of the Gyeongsang provinces...

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Currently, I Corps is the largest corps in the ROK Army

Republic of Korea Army

The Republic of Korea Army is the largest of the military branches of the South Korean armed forces with 520,000 members as of 2010...

. I Corps is organized with three infantry divisions, one mechanized infantry division, and several separate brigades.