Overview of the Korean War

The Forgotten Conflict

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.

​Corporal Peter McDonald, USMC / Wikimedia Commons / Public Domain

Fought from June 1950 to July 1953, the Korean War saw Communist North Korea invade its southern, democratic neighbor. Backed by the United Nations, with many of the troops furnished by the United States, South Korea resisted and fighting ebbed and flowed up and down the peninsula until the front stabilized just north of the 38th Parallel. A bitterly contested conflict, the Korean War saw the United States follow its policy of containment as it worked to block aggression and halt the spread of Communism. As such, the Korean War may be seen as one of the many proxy wars fought during the Cold War.

Causes of the Korean War

Kim Il-sung

Public Domain

Liberated from Japan in 1945 during the final days of World War II, Korea was divided by the Allies with the United States occupying the territory to the south of the 38th Parallel and the Soviet Union the land to the north. Later that year it was decided that the country would be reunited and made independent after a five-year period. This was later shortened and elections in North and South Korea were held in 1948. While the Communists under Kim Il-sung (above) took power in the north, the south became democratic. Supported by their respective sponsors, both governments wished to reunite the peninsula under their particular ideology. After several border skirmishes, North Korea invaded south on June 25, 1950, opening the conflict.

First Shots to the Yalu River: June 25, 1950-October 1950

US troops defend the Pusan Perimeter
US troops defend the Pusan Perimeter. Photograph Courtesy of the US Army

Immediately condemning the North Korean invasion, the United Nations passed Resolution 83 which called for military assistance for South Korea. Under the UN banner, President Harry Truman ordered American forces to the peninsula. Driving south, the North Koreans overwhelmed their neighbors and forced them into a small area around the port of Pusan. While fighting raged around Pusan, UN commander General Douglas MacArthur masterminded a daring landing at Inchon on September 15.  Along with a breakout from Pusan, this landing shattered the North Korean offensive and UN troops drove them back over the 38th Parallel. Advancing deep into North Korea, UN troops hoped to end the war by Christmas despite Chinese warnings about intervening.

China Intervenes: October 1950-June 1951

Battle of Chosin Reservoir
Battle of Chosin Reservoir. Photograph Courtesy of the US Marine Corps

Though China had been warning of intervention for much of the fall, MacArthur dismissed the threats. In October, Chinese forces crossed the Yalu River and entered combat. The next month, they unleashed a massive offensive that sent UN forces reeling south after engagements like the Battle of Chosin Reservoir. Forced to retreat to the south of Seoul, MacArthur was able to stabilize the line and counterattacked in February. Re-taking Seoul in March, UN forces again pushed north. On April 11, MacArthur, who had been clashing with Truman, was relieved and replaced by General Matthew Ridgway. Pushing across the 38th Parallel, Ridgway repelled a Chinese offensive before halting just north of the border.

A Stalemate Ensues: July 1951-July 27, 1953

Battle of Chiperi
Battle of Chiperi. Photograph Courtesy of the US Army

With the UN halt north of the 38th Parallel, the war effectively became a stalemate. Armistice negotiations opened in July 1951 at Kaesong before moving to Panmunjom. These talks were hampered by POW issues as many North Korean and Chinese prisoners did not wish to return home. At the front, UN airpower continued to hammer the enemy while offensives on the ground were relatively limited. These typically saw both sides battling over hills and high ground along the front. Engagements in this period included the Battles of Heartbreak Ridge (1951), White Horse (1952), Triangle Hill (1952), and Pork Chop Hill (1953). In the air, the war saw the first major occurrences of jet vs. jet combat as aircraft dueled in areas such as "MiG Alley."

Aftermath of the War

Military police of the Joint Security Area
Military police of the Joint Security Area stand watch at the observation tower, March 1997. Photograph Courtesy of the US Army

The negotiations at Panmunjom finally bore fruit in 1953 and an armistice went into effect on July 27. Though fighting ended, no formal peace treaty was concluded. Instead, both sides agreed to the creation of a demilitarized zone along the front. Approximately 250 miles ​long and 2.5 miles wide, it remains one of the most heavily militarized borders in the world with both sides manning their respective defenses. Casualties in the fighting numbered around 778,000 for UN/South Korean forces, while North Korea and China suffered around 1.1 to 1.5 million. In the wake of the conflict, South Korea developed one of the world's strongest economies while North Korea remains an isolated pariah state.

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Hickman, Kennedy. "Overview of the Korean War." ThoughtCo, Apr. 5, 2023, thoughtco.com/the-korean-war-an-overview-2360860. Hickman, Kennedy. (2023, April 5). Overview of the Korean War. Retrieved from https://www.thoughtco.com/the-korean-war-an-overview-2360860 Hickman, Kennedy. "Overview of the Korean War." ThoughtCo. https://www.thoughtco.com/the-korean-war-an-overview-2360860 (accessed June 10, 2023).