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Korean War Timeline: Key Dates, Battles and the Armistice That Never Became a Peace Treaty

From a divided peninsula to a three-year war and a ceasefire that still holds: the dates that define Korea's first hot war of the Cold War.

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1945 Korea divided at the 38th parallel June 25, 1950 North Korea invades the South August–September 1950 Pusan Perimeter holds September 15, 1950 Inchon landing October–November 1950 China enters the war April 1951 MacArthur relieved July 1951 Truce talks begin July 27, 1953 Armistice signed

1945 Korea is divided along the 38th parallel

At the end of World War II, the United States and the Soviet Union agree to a temporary division of Korea at the 38th parallel to oversee the removal of Japanese forces; the line hardens into a border between two rival governments.

June 25, 1950 North Korean forces cross the 38th parallel

Kim Il Sung's army attacks South Korea, and Seoul falls within three days. The United States leads a United Nations-authorized force to defend the South.

August–September 1950 UN forces hold the Pusan Perimeter

Pushed back to the southeastern corner of the peninsula, American, South Korean and allied troops hold a defensive line around the port of Pusan.

September 15, 1950 The Inchon landing turns the war

General Douglas MacArthur's amphibious assault behind North Korean lines cuts their supply routes, and UN forces retake Seoul before pushing north of the 38th parallel.

October–November 1950 Chinese forces launch their First Offensive

Chinese troops cross into Korea and open their First Offensive on October 25, driving UN forces back and turning a near-victory into a long retreat.

April 1951 Truman relieves General MacArthur

President Truman removes MacArthur from command after public disagreement over limited war, and General Matthew Ridgway takes over.

July 1951 Armistice negotiations open

With the front settling near the 38th parallel, both sides begin ceasefire talks that will drag on for two years.

July 27, 1953 The Korean Armistice Agreement is signed

Commanders for the Chinese and North Korean armies and the United Nations Command sign an armistice that creates the Demilitarized Zone. No peace treaty follows.

Last updated: November 2026

History Timelines. (November 2026). Korean War Timeline: Key Dates and Events, 1950-1953. Retrieved from https://history-timelines.org.uk/events/korean-war/

This Korean War timeline follows the conflict from the 1945 division of Korea to the armistice signed on July 27, 1953, covering the invasion, the swings of the front line and the long stalemate that followed. It is built as a dated reference: each turning point is pinned to a real date, and each section explains why that moment changed the course of the war.

When Was the Korean War? Division and Invasion

The question of when was the Korean War has a short answer, June 25, 1950 to July 27, 1953, but the causes start earlier. At the end of World War II the United States and the Soviet Union agreed to divide Korea at the 38th parallel to oversee the removal of Japanese troops. What was meant as a temporary arrangement hardened into two governments, each claiming the whole peninsula. In June 1950 Kim Il Sung’s army crossed the line, and Seoul was captured by June 28. The United States, acting through a United Nations-authorized force, came to the South’s defense, which is why the war is often described as the first armed conflict of the Cold War. For the first few weeks the defenders were outnumbered and short of equipment, and the speed of the collapse surprised Washington as much as Seoul.

A folded military map of the Korean peninsula on a wooden table beside a lantern, field radio, binoculars and brass compass

Korean War Dates: From Pusan to the Yalu

The first months produced the most dramatic reversals of the whole war. By late summer 1950 UN forces were pinned inside the Pusan Perimeter in the far southeast, close to losing the peninsula altogether. On September 15, MacArthur’s landing at Inchon, far up the western coast, cut North Korean supply lines and allowed the recapture of Seoul. UN troops then crossed the 38th parallel, a decision that changed the nature of the war: the aim shifted from restoring South Korea to unifying the peninsula by force. China answered. Its First Offensive began on October 25, 1950, and in the weeks that followed UN forces fell back in a bitter winter retreat. Seoul changed hands again in early January 1951. Anyone working through korean war dates should note how quickly the front moved in these first eight months, and how little it moved afterwards. The cost of that early see-saw was borne largely by civilians, who were displaced in very large numbers as the line swept up and down the peninsula.

A Korean War Timeline of Events: Stalemate and Truce

From spring 1951 the war became a grinding contest along a line close to the original border. In April, Truman relieved MacArthur, who had argued publicly for a wider war; the dismissal set a precedent that elected leaders, not field commanders, decide the limits of a conflict. Truce talks opened in July 1951, but fighting continued for two more years over prisoner exchanges and hills that changed hands at heavy cost. This korean war timeline of events turns slowly in its final phase, because the diplomacy, not the front, was where the war was being decided. The final year was marked by heavy fighting on a few contested ridgelines, even as negotiators argued about how prisoners of war would be returned. Dwight Eisenhower was elected president in 1952 and Stalin died in March 1953, and an armistice followed that July.

Korean War Facts Timeline: What the Armistice Did and Did Not Do

A korean war facts timeline has to end with a caveat, because the usual shorthand of a war that was won or lost does not fit. Neither side achieved its aim. The armistice of July 27, 1953 stopped the shooting and created the Demilitarized Zone, but it was a ceasefire between military commands, not a peace treaty. Technically the war has never formally ended. The peninsula remains divided, and the border area is among the most heavily fortified in the world. The war also reshaped American policy: it also marked the first time the United Nations sent a combined military force to repel an invasion, and it fed a large rise in defense spending and a commitment to contain communism by force, which led directly toward Vietnam. For the wider rivalry behind it, see the Cold War timeline, and for the president who made the decisions, Harry S. Truman.

Frequently Asked Questions

When was the Korean War?

The Korean War ran from June 25, 1950, when North Korean forces crossed the 38th parallel, to July 27, 1953, when the armistice was signed.

Who fought in the Korean War?

North Korea, backed by China and the Soviet Union, fought South Korea and a United Nations force led by the United States.

Why did the Korean War start?

It grew from the postwar division of Korea at the 38th parallel and the rivalry between two governments that each claimed to rule the whole country; North Korea's June 1950 invasion set it off.

Did the Korean War end with a peace treaty?

No. The 1953 armistice ended the fighting and created the Demilitarized Zone, but no peace treaty was ever signed, so the two Koreas remain technically at war.

What was the Inchon landing?

The Inchon landing on September 15, 1950 was an amphibious assault led by General Douglas MacArthur that cut North Korean supply lines and led to the recapture of Seoul.