The Battle of Battle Mountain was an engagement between United Nations Command (UN) and North Korean forces early in the Korean War from August 15 to September 19, 1950, on and around the Sobuk-san mountain area in South Korea. It was one of several large engagements fought simultaneously during the Battle of Pusan Perimeter. The battle ended in a victory for the UN after large numbers of United States Army (US) and Republic of Korea Army (ROK) troops were able to prevent a Korean People's Army (KPA) division from capturing the mountain area.
Operating in defense of Masan, the US 25th Infantry Division placed its 24th Infantry Regiment and 5th Infantry Regiment on Sobuk-san to defend its two peaks, P'il-bong and Hill 665, which would later be known as "Battle Mountain." What followed was a month-long struggle with the KPA 6th Division, in which Battle Mountain changed hands 20 times.
During the deadlock, neither side was able to secure a definite victory in capturing the mountaintop, but the US forces succeeded in their mission of preventing the KPA from advancing beyond Battle Mountain, paving the way for the KPA's eventual defeat and withdrawal.
Background
Outbreak of war
Following the June 25, 1950, outbreak of the Korean War as a result of the invasion of South Korea by North Korea, the United Nations committed troops to the conflict in support of South Korea. The United States, subsequently dispatched ground forces to the Korean peninsula with the goal of pushing back the North Korean invasion and preventing South Korea from collapsing. However, the number of US forces in the Far East had been steadily decreasing since the end of World War II, five years earlier, and at the time the closest forces were the 24th Infantry Division, headquartered in Japan. The division was understrength however, and most of its equipment was antiquated due to reductions in military spending. Regardless, the 24th was ordered to South Korea.
The 24th Infantry Division was the first US unit sent into Korea with the mission to take the initial "shock" of KPA advances, delaying the much larger KPA units to buy time to allow reinforcements to arrive. The division was consequently alone for several weeks while the 1st Cavalry Division and the 7th and 25th Infantry Divisions moved into position, along with other Eighth United States Army supporting units. Advance elements of the 24th Division were badly defeated in the Battle of Osan on July 5, the first encounter between US and KPA forces. For the first month after the defeat at Osan, 24th Division was repeatedly defeated and forced south by superior KPA numbers and equipment. The regiments of the 24th Infantry were systematically pushed south in engagements around Chochiwon, Chonan, and Pyongtaek. The 24th made a final stand in the Battle of Taejon, where it was almost completely destroyed but delayed KPA forces from advancing until July 20. By that time, the Eighth Army's force of combat troops were roughly equal to KPA forces attacking the region, with new UN units arriving every day.
North Korean advance
With Taejon captured, KPA forces attempted to envelop the Pusan Perimeter. The KPA 4th and 6th Divisions advanced south in a wide flanking maneuver. The two divisions were forced to spread their units along a thin line, but managed to penetrate the UN's left flank with armor and superior numbers, repeatedly pushing back UN forces. UN forces were pushed back repeatedly before finally halting the KPA advance in a series of engagements in the southern section of the country. The 3rd Battalion, 29th Infantry Regiment, newly arrived in the country, sustained massive casualties at Hadong in a coordinated ambush on July 27 that opened a pass to the Pusan area. Soon after, KPA forces took Chinju to the west, pushing back the US 19th Infantry Regiment and leaving routes to the Pusan area open for more KPA attacks. US formations were subsequently able to defeat and push back the KPA on the flank in the Battle of the Notch on August 2. Suffering mounting losses, the KPA force in the west withdrew for several days to re-equip and receive reinforcements. This granted both sides a reprieve to prepare for the attack on the Pusan Perimeter.