Korean War: Battle of Chosin Reservoir

Battle of Chosin Reservoir
A column of troops and armor of the 1st Marine Division move through communist Chinese lines during their successful breakout from the Chosin Reservoir in North Korea. Photograph Courtesy of the Department of Defense

The Battle of Chosin Reservoir was fought from November 26 to December 11, 1950 during the Korean War (1950-1953). Following the Chinese decision to intervene in the Korean War in October, their forces began crossing the Yalu River in large numbers. Encountering elements of Major General Edward Almond's X Corps, including the 1st Marine Division, they attempted to overwhelm the Americans near the Chosin Reservoir. Fought in bitterly cold conditions, the resulting battle quickly entered US Marine Corps lore as the Marines, with support from the US Army, fought tenaciously to escape from the Chinese. After more than two weeks, they succeeded in breaking out and were ultimately evacuated from Hungnam.

Fast Facts: Inchon Invasion

  • Conflict: Korean War (1950-1953)
  • Dates: November 26 to December 11, 1950
  • Armies & Commanders:
    • United Nations
      • General Douglas MacArthur
      • Major General Edward Almond, X Corps
      • Major General Oliver P. Smith, 1st Marine Division
      • approx. 30,000 men
    • Chinese
      • General Song Shi-Lun
      • approx. 120,000 men
  • Casualties:
    • United Nations: 1,029 killed, 4,582 wounded, and 4,894 missing
    • Chinese: 19,202 to 29,800 casualties


On October 25, 1950, with General Douglas MacArthur's United Nations forces closing in a victorious end to the Korean War, Communist Chinese forces began pouring across the border. Striking the spread out UN troops with overwhelming force, they compelled them to retreat all across the front. In northeastern Korea, the US X Corps, led by Major General Edward Almond, was strung out with its units unable to support each other. Those units near the Chosin (Changjin) Reservoir included the 1st Marine Division and elements of the 7th Infantry Division.

MacArthur at Inchon
General Douglas MacArthur during the Inchon landings, September 1950. National Archives and Records Administration

Chinese Invasion

Advancing quickly, the Ninth Army Group of the People's Liberation Army (PLA) blunted X Corps advance and swarmed around the UN troops at Chosin. Alerted to their predicament, Almond ordered the commander of the 1st Marine Division, Major General Oliver P. Smith, to begin a fighting retreat back towards the coast.

Commencing on November 26, Smith's men endured extreme cold and severe weather. The next day, the 5th and 7th Marines attacked from their positions near Yudam-ni, on the west bank of the reservoir, with some success against the PLA forces in the area. Over the next three days the 1st Marine Division successfully defended their positions at Yudam-ni and Hagaru-ri against Chinese human wave assaults. On November 29, Smith contacted Colonel "Chesty" Puller, commanding the 1st Marine Regiment, at Koto-ri and asked him to assemble a task force to re-open the road from there to Hagaru-ri.

"Chesty" Puller
Colonel Lewis "Chesty" Puller, November 1950. US Marine Corps

Hell Fire Valley

Complying, Puller formed a force consisting of Lieutenant Colonel Douglas B. Drysdale's 41 Independent Commando (Royal Marines Battalion), G Company (1st Marines), B Company (31st Infantry), and other rear echelon troops. Numbering 900 men, the 140-vehicle task force departed at 9:30 AM on the 29th, with Drysdale in command. Pushing up the road to Hargaru-ri, the task force became bogged down after being ambushed by Chinese troops. Fighting in an area that was dubbed "Hell Fire Valley," Drysdale was reinforced by tanks sent by Puller.

Chosin Reservoir Map
Battle of Chosin Reservoir Map. US Army

Pressing on, Drysdale's men ran a gauntlet of fire and reached Hagaru-ri with the bulk of 41 Commando, G Company, and the tanks. During the attack, the B Company, 31st Infantry, became separated and isolated along the road. While most were killed or captured, some were able to escape back to Koto-ri. While the Marines were fighting to the west, the 31st Regimental Combat Team (RCT) of the 7th Infantry was battling for its life on the eastern shore of the reservoir.

Battle of Chosin Reservoir
US Marine engage Chinese forces in Korea, 1950. US Marine Corps

Fighting to Escape

Repeatedly assaulted by the 80th and 81st PLA divisions, the 3,000-man 31st RCT was worn down and overrun. Some survivors of the unit reached the Marine lines at Hagaru-ri on December 2. Holding his position at Hagaru-ri, Smith ordered the 5th and 7th Marines to abandon the area around Yudam-ni and link up with the rest of the division. Fighting a brutal three-day battle, the Marines entered Hagaru-ri on December 4. Two days later, Smith's command began fighting their way back to Koto-ri.

Battling overwhelming odds, the Marines and other elements of X Corps attacked continuously as they moved towards the port of Hungnam. A highlight of the campaign occurred on December 9, when a bridge was constructed over a 1,500-ft. gorge between Koto-ri and Chinhung-ni using prefabricated bridge sections dropped by the US Air Force. Cutting through the enemy, the last of the "Frozen Chosin" reached Hungnam on December 11.


While not a victory in the classic sense, the withdrawal from the Chosin Reservoir is revered as a high point in the history of the US Marine Corps. In the fighting, the Marines and other UN troops effectively destroyed or crippled seven Chinese divisions which attempted to block their progress. Marine losses in the campaign numbered 836 killed and 12,000 wounded. Most of the latter were frostbite injuries inflicted by the severe cold and winter weather.

US Army losses numbered around 2,000 killed and 1,000 wounded. Precise casualties for the Chinese are not known but are estimated between 19,202 to 29,800. Upon reaching Hungnam, the veterans of Chosin Reservoir were evacuated as part of the large amphibious operation to rescue UN troops from northeastern Korea.



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Hickman, Kennedy. "Korean War: Battle of Chosin Reservoir." ThoughtCo, Sep. 16, 2020, thoughtco.com/korean-war-battle-of-chosin-reservoir-2360849. Hickman, Kennedy. (2020, September 16). Korean War: Battle of Chosin Reservoir. Retrieved from https://www.thoughtco.com/korean-war-battle-of-chosin-reservoir-2360849 Hickman, Kennedy. "Korean War: Battle of Chosin Reservoir." ThoughtCo. https://www.thoughtco.com/korean-war-battle-of-chosin-reservoir-2360849 (accessed March 20, 2023).