My father fought in the Second Infantry Division in the Korean War. Following is the Wikipedia account of the 2ID's role in that conflict:
"With the outbreak of hostilities in Korea during the summer of 1950, the 2nd Infantry Division was quickly alerted for movement to the Far East Command. The division arrived in Korea, via Pusan on July 23, becoming the first unit to reach Korea directly from the United States. Initially employed piecemeal, the entire division was committed as a unit on August 24, 1950, relieving the 24th Infantry Division at the Naktong River Line. The first big test came when the North Koreans struck in a desperate human wave attack on the night of August 31. In the 16-day battle that followed, the division’s clerks, bandsmen, technical and supply personnel joined in the fight to defend against the attackers.
Shortly thereafter, the 2ID was the first unit to break out of the Pusan Perimeter and they led the Eighth Army drive to the Manchurian Border. Now within fifty miles of the Manchurian border when Chinese forces entered the fight, soldiers of the 2nd Infantry Division were given the mission of protecting the rear and right flank of the Eighth Army as it retired to the South. Fighting around Kunu-ri cost the division nearly one third of its strength, but was ten times more costly to the enemy and the way was kept open. The Chinese winter offensive was finally blunted by the 2nd Infantry Division on January 31 at Wonju. Taking up the offensive in a two-prong attack in February 1951, the Division repulsed a powerful Chinese counter-offensive in the epic battles of Chipyong-ni and Wonju. The United Nations front was saved and the general offensive continued.
Again in April and May 1951, the 2nd Infantry Division was instrumental in smashing the communist's spring offensive. For its part in this action the 2nd Infantry Division was awarded the Presidential Unit Citation. What followed were alternating periods of combat and rest, with the division participating in the Battle of Bloody Ridge and Battle of Heartbreak Ridge. Finally, on April 9, 1954, the Division was moved to a rear area near Chi-po-ri and on August 20, 1954, four years after its last unit arrived in Korea, the 2ID was alerted for re-deployment to the United States.
The more than 7,000 combat deaths of the 2nd Division in Korea are the highest total among any modern U.S. division in any war since 1900. Its nearly 15000 combat deaths in World War I, World II, and Korea are the greatest combined total of all U.S. divisions and equal its average combat strength."