The Korean War Chronology
PHASE 1: 27 June-15 September 1950
(UN Defensive)
25 June | North Korean forces cross border with South Korea. North Korean People's Army (NKPA) numbers approximately 135,000 men; Republic of Korea (ROK) Army contains 98,000 soldiers. |
28 June | NKPA forces capture Seoul. |
1 July | First U.S. ground combat troops, Task Force Smith (1st Battalion, 21st Infantry, 24th Infantry Division), arrive in Korea. |
3 July | Inchon falls to the NKPA. |
5 July | Task Force Smith engages and delays advancing NKPA forces at Osan in first U.S. ground action of the war. |
8-12 July | 21st Infantry stalls NKPA advances at Chochiwon. |
10-18 July | 25th Infantry and 1st Cavalry Divisions begin movement to Korea from Japan; 29th Regimental Combat Team sails from Okinawa for Korea; 2d Infantry Division prepares to embark from Seattle. |
13-16 July | 19th and 34th Infantry Regiments, 24th Infantry Division, fight delaying actions at Kum River line. |
19 July | 24th Infantry Division begins defense of Taejon. |
20 July | Taejon is captured by NKPA; 24th Infantry, 25th Infantry Division, captures Yechon. |
25 July | 29th Regiment engages the enemy near Chinju. |
31 July | 5th Regimental Combat Team arrives in Korea from Hawaii. |
4 August | Naktong (Pusan) Perimeter is set up. |
8-18 August | NKPA attempts to penetrate Naktong (Pusan) Perimeter and is repelled by 24th, 2d, and 25th Infantry Divisions along with Marine elements in the First Battle of the Naktong Bulge. |
15-20 August | Elements of 23d and 27th Infantry Regiments and ROK 1st Division successfully defend Naktong (Pusan) Perimeter in the Battle of the Bowling Alley (west of Taegu). |
31 August-19 September | Second Battle of the Naktong Bulge. |
PHASE 2: 16 September-2 November 1950
(UN OFFENSIVE)
15 September | U.S. X Corps, with the 1st Marine Division, in the lead, conducts amphibious landing at Inchon. |
16 September | U.S. Eighth Army begins its offensive northward out of the Pusan Perimeter. |
20 September | 1st Marine Division drives northeast across Han River. |
26 September | X Corps' 31st Infantry Regiment, 7th Infantry Division, moving east from Inchon, links up with Eighth Army's 7th Cavalry Regiment, 1st Cavalry Division, south of Suwon. | 27 September | U.S. and Republic of Korea (ROK) forces capture Seoul, the South Korean capital. |
1 October | ROK I Corps crosses 38th Parallel and then advances up the east coast. |
6-7 October | Two ROK II Corps divisions cross 38th Parallel in central Korea. |
9 October | U.S. Eighth Army forces cross 38th Parallel north of Kaesong and attack northward toward P'yongyang, the North Korean capital. |
10 October | ROK I Corps captures the major port of Wonsan. |
14-17 October | 7th Infantry Division loads on ships at Pusan in preparation for amphibious landings by X Corps along the northeastern coast above the 38th Parallel. |
19 October | 1st ROK Division and U.S. 1st Cavalry Division capture P'yongyang. |
25 October | Communist Chinese Forces (CCF) offensive operations begin north of Unsan with fighting between CCF and ROK forces; first Chinese soldier is captured. |
26 October | 1st Marine Division, X Corps, lands at Wonsan. ROK forces reach the Yalu River at Chosan. |
29 October | U.S. 7th Division lands at Iwon. |
1-2 November | First U.S. battle with CCF, near Unsan. |
Phase 3: 3 November 1950-24 January 1951
(CCF INTERVENTION)
3-6 November | Communist Chinese Forces (CCF) offensive continues in Eighth Army and X Corps zones. |
11 November | X Corps resumes advance north. |
24 November | Eighth Army moves north from the Chongchon River. |
25 November | Chinese forces attack Eighth Army center and right. |
27 November | X Corps attacks from west in support of Eighth Army; Chinese forces strike X Corps at Chosin Reservoir. |
29 November | Eighth Army begins general withdrawal from Chongchon River line to defensive line at P'yongyang. |
29 November-1 December | Chinese forces devastate U.S. 2d Infantry Division as it guards Eighth Army withdrawal. |
30 November | X Corps starts retreat to port of Hungnam. |
5 December | Eighth Army falls back from P'yongyang. |
11-24 December | X Corps loads on ships for evacuation to Pusan; General Almond sails on Christmas Eve. |
23 December | General Walker is killed in auto accident north of Seoul. |
26 December | Lt. Gen. Matthew B. Ridgway arrives in Korea as Eighth Army commander. |
31 December-5 January | New CCF offensive begins. |
4 January | Seoul falls; Eighth Army pulls back to line forty miles south of Seoul. |
5 January | Port of Inchon is abandoned. |
7-15 January | Enemy offensive subsides; UNC situation stabilizes intelligence sources report many enemy units had withdrawn to refit. |
15 January | Army Chief of Staff General J. Lawton Collins, on a visit to Korea, declares that "we are going to stay and fight." |
PHASE 4: 24 January-21 April 1951
(First UN Counteroffensive)
22 April-July 1951 (CCF Spring Offensive)
25 January | Eighth Army counterattacks in Operation THUNDERBOLT, which starts in the west and gradually expands eastward. |
10 February | In the west, Inch'on is recaptured, as I Corps approaches the Han River |
11-12 February | Chinese forces attack X Corps, forcing advancing ROK units to fall back toward Wonju. |
13-15 February | Battle of Chipyong-ni. |
18 February | Reports confirm an enemy withdrawal along the entire central front. |
21 February | Eighth Army launches Operation KILLER, a general advance north by IX and X Corps |
28 February | Enemy resistance south of the Han River collapses. |
7 March | General Ridgeway begins Operation RIPPER; the objective is Line Idaho, just south of the 38th Parallel. |
14-15 March | UN troops enter Seoul, the South Korean capital. |
31 March | Eighth Army is positioned along the Idaho line. |
2-5 April | General Ridgeway puts Operation RUGGED into motion; the objective is Line Kansas, some ten miles above the 38th Parallel. |
9 April | The I and IX Corps and the ROK I Corps reach the Kansas line; the two U.S. corps continue to advance farther north. |
11 April | General MacArthur is relieved as UNC commander; General Ridgeway succeeds him. |
14 April | General Van Fleet assumes command of Eighth Army. |
22 April | The expected Chinese and North Korean spring offensive begins, with the strongest attacks in the west, toward Seoul. |
30 April | The enemy offensive is stopped just north of Seoul. |
15-20 May | The Chinese and North Koreans resume the offensive, focusing on the east-central region; General Van Fleet begins a counterattack. |
31 May | The Eighth Army advances nearly to Line Kansas. |
1 June | General Van Fleet strengthens the Kansas line and sends forces farther north, toward Line Wyoming. |
23 June | The Soviet Union calls for armistice talks. |
PHASE 5: 9 July 1951-27 July 1953 (UN Summer-Fall Offensive 1951)
(Second Korean Winter) (Korea, Summer- Fall 1952)
(Third Korean Winter) (Korea, Summer 1953)
10 July 1951 | Armistice talks begin at Kaesong. |
23 August | Communist side breaks off negotiations. |
5 September | North Koreans abandon Bloody Ridge, after UN forces, led by U.S. 2d Infantry Division's 9th Infantry, outflank it. |
12 September-13 October | 2d Infantry Division, using the 72d Tank Battalion to tactical advantage, seizes Heartbreak Ridge. |
3-19 October | Five UN divisions advance to Line Jamestown, some four miles beyond the Wyoming line, to protect the Seoul-Chorwon railway. |
25 October | Armistice talks resume, now at Panmunjom. |
12 November | General Ridgway, the UNC commander, instructs General Van Fleet to cease Eighth Army offensive operations and to assume an "active defense." |
12 May 1952 | General Mark W. Clark assumes command of the UNC. |
8 October | UN delegation calls an indefinite recess to armistice talks, reflecting a long lack of any progress. |
11 February 1953 | Lt. Gen. Maxwell D. Taylor takes command of the Eighth Army. |
26 April | Armistice talks begin again. |
6-11 July | General Taylor abandons Pork Chop Hill, a 7th Infantry Division outpost, to the Chinese as not worth further fighting. |
13-20 July | Chinese launch a six-division attack against ROK II Corps and U.S. IX Corps south of Kumsong; after falling back some eight miles to below the Kumsong River, UN forces regain the high ground along the river. |
27 July | Armistice agreement is signed at 1000; all fighting stops twelve hours later; both sides have three days to withdraw two kilometers from the cease-fire line. |
Posters Available as PDF Files:
Phase 1, 27 June-15 September 1950
PDF 686KB
- (UN Defensive)
Phase 2, 16 September-2 November 1950
PDF 713KB
- (UN Offensive)
Phase 3, 3 November 1950-24 January 1951
PDF 716KB
- (CCF Intervention) Offensive)
Phase 4, 25 January-21 April 1951 22 April-8 July 1951
PDF 839KB
- (First UN Counteroffensive) (CCF Spring Offensive)
Phase 5, 9 July 1951-27 July 1953 (Last Offensive)
PDF 861KB
- (UN Summer-Fall Offensive 1951)
- (Second Korean Winter)
- (Korea, Summer- Fall 1952)
- (Third Korean Winter)
- (Korea, Summer 1953)