1950
25 Jun North Korean People’s Army, with 60,000 troops and 100 Russian tanks, crosses 38th Parallel to invade South Korea.
25 Jun United Nations Security Council calls for end of aggression and withdrawal of NKPA troops.
27 Jun UN, adopting a U.S. resolution, proclaims NKPA attack a breach of world peace. Asks member nations to assist ROK in repelling invasion.
27 Jun Pres Truman orders U.S. air-sea units to support ROK and for U.S. Seventh Fleet to neutralize Formosan Strait.
28 Jun NKPA captures Seoul, South Korean capital.
29 Jun Pres Truman orders naval blockade of Korean coast; authorizes Far East Commander, Gen MacArthur, to send U.S. ground troops into Korea.
30 Jun Pres Truman receives Congressional authorization to order into active service any or all reserve components of Armed Forces, for a period of 21 months.
  2 Jul CNO directs that Marine reinforced regiment with supporting air be prepared for assignment to Far East.
  2 Jul CinCFE requests Marine RCT-air unit for Far East. This was inception of 1st Provisional Marine Brigade, formed less than a week later.
  3 Jul Inchon captured by North Koreans.
  5 Jul-4 Aug UNC fights series of delaying actions in Korea.
  7 Jul U.N. Security Council authorizes formation of a United Nations Command as counterforce against NKPA aggression.
  7 Jul 1st ProvMarBrig activated at Camp Pendleton, under BGen Edward A. Craig. Basic elements of 6,534-man Brigade are 5th Marines and MAG-33.
  8 Jul Gen MacArthur named Commander, UNC.
10 Jul CinCUNC asks Joint Chiefs of Staff to authorize expansion of Marine Brigade to full war-strength division.
12–14 Jul 1st ProvMarBrig embarks for Korean theater.
12 Jul LtGen Walton H. Walker named CG, Eighth U.S. Army in Korea.
19 Jul CinCUNC makes 2d request for Marine division.
19 Jul Pres Truman authorizes Defense Dept to call up reserve units and individuals.
19 Jul CMC alerts Marine Corps organized reserve units for call to active duty following Presidential announcement.
20 Jul CMC, Gen Clifton B. Cates, orders to duty Organized Marine Corps ground reserve units, consisting of 22 units and 4,830 personnel. Partial callup for 6,000 air reservists in 30 Marine VMF and 12 MGCI squadrons.
20 Jul Taejon, temporary ROK capital, captured.
21 Jul CinCUNC makes 3d request for Marine division.
25 Jul UNC defense at Pusan deteriorates. CinCUNC orders 1st ProvMarBrig directly to Korea.
25 Jul JCS directs Marine Corps to build 1stMarDiv to war-strength.
31 Jul Masan and Chinju fall to enemy.
  2–3 Aug 1st ProvMarBrig arrives Pusan. Moves to bivouac area near Masan.
  3 Aug First Marine air strike launched by VMF-214.
  4 Aug Pusan Perimeter established by UNC in southeastern end of Korea.
  4 Aug First evacuation of casualties from Pusan by Marine VMO-6 helicopters.
  6 Aug First air mission flown by VMF-323.
  6–8 Aug CinCUNC confers with U.S. military-diplomatic officials about proposed Inchon amphibious landing.
  7–13 Aug Marine Brigade engaged in first combat operations at Chinju.
10 Aug First Marine helicopter rescue made by VMO-6 to recover downed pilot.
10–24 Aug 1stMarDiv units embark for Korea.
16 Aug EUSAK X Corps activated for coming Inchon-Seoul operation. Principal elements are 1stMarDiv and Army 7thInfDiv.
17 Aug Marine Brigade opens battle for Obong-ni (“No Name”) Ridge, leading way to destruction of enemy bridgehead at Naktong and first UNC victory in Korea.
17 Aug 7th Marines activated at Camp Pendleton and on 1 Sep embarks for Far East, arriving 21 Sep.
  1–5 Sep NKPA launches all-out offensive to break UNC perimeter defense at Pusan. In Second Naktong Battle, Brigade contains enemy at Yongsan.
13 Sep 1st ProvMarBrig deactivated and absorbed by 1stMarDiv for Inchon operation.
15 Sep D-Day, Inchon amphibious assault, spearheaded by 1stMarDiv.
17 Sep 1stMarDiv (5th Marines) recaptures Kimpo Airfield.
19–25 Sep Enemy resistance at Pusan begins to collapse. NKPA troops in retreat north from Pusan.
27 Sep 1stMarDiv recaptures Seoul. ROK Capital officially liberated 29 Sep.
30 Sep Communist China Foreign Minister Chou En-lai warns: “The Chinese people will not supinely tolerate seeing their neighbors being savagely invaded by the imperialists.”
30 Sep-1 Oct ROK 3d Div crosses 38th Parallel in pursuit of retreating NKPA.
  7 Oct UN General Assembly authorizes UNC forces to cross 38th Parallel to defeat NKPA.
10 Oct Wonsan, east coast port at 39th Parallel, captured by ROK troops.
10 Oct Chinese repeat warning of intervention in Korean conflict.
16 Oct First Chinese Communist troops secretly enter Korea from Manchuria.
19 Oct Pyongyang, North Korean Capital at 39th Parallel, captured by EUSAK.
26 Oct Chinese troops attack ROK units at Yalu River and points south of Sino-Korean border.
26 Oct 1stMarDiv lands at Wonsan, establishes security for port, and drives north.
  1 Nov UNC forward elements reach positions along Yalu. First Russian-built MIG appears along Yalu to attack U.S. aircraft.
  2 Nov Strong Chinese and NKPA forces attack EUSAK at Unsan, causing withdrawal across Chongchon River. First identification of Chinese Communist Forces (CCF) in Korea.
  3–7 Nov Initial Marine encounter with CCF. 7th Marines units defeat major elements of 124th CCF Division.
  6 Nov MacArthur warns JCS that movement of CCF across Yalu threatens UNC position.
15 Nov Marine units reach Chosin Reservoir area in X Corps drive north.
24 Nov MacArthur announced “win the war” offensive. EUSAK begins advance toward Yalu.
26–27 Nov CCF, 200,000-strong, attack EUSAK troops forcing withdrawal. 1stMarDiv isolated at Yudam-ni, west of Chosin. MSR cut.
28 Nov-3 Dec 1stMarDiv turns back CCF attacks. Prepares to move south. Regroups at Hagaru-ri for drive to Hungnam.
  4 Dec Pyongyang recaptured by enemy.
  5–7 Dec 1stMarDiv evacuates wounded by air and fights through to Koto-ri.
  6 Dec Innovation of using airborne TADC as tactical CP to control air support.
10 Dec First Marine jet squadron to fly in combat, VMF-311, begins operations.
11 Dec 1stMarDiv completes fighting breakout from Chosin entrapment. Begins march to join rest of X Corps at Hungnam.
15 Dec 1stMarDiv deployed from Hungnam to Pusan.
15 Dec UNC establishes new defensive line at 38th Parallel.
18 Dec-27 Jan Marine division routs enemy guerrilla forces in Masan-Pohang-Sondong-Andong area.
23 Dec EUSAK CG Walker killed in jeep accident. Gen Matthew B. Ridgway named to succeed him.
24 Dec Hungnam evacuation completed by X Corps.
29 Dec Large enemy buildup reported north of 38th Parallel, preparing for new attack.
1951
31 Dec-1 Jan Enemy launches all-out offensive against UNC across 38th Parallel, pushing EUSAK back 10–12 miles.
  4 Jan Seoul recaptured by Communists.
  7–15 Jan Enemy offensive halted, UNC sets up new defense line along Pyongtaek-Wonju axis, at 37th Parallel.
25 Jan UNC reassumes offensive. Operation THUNDERBOLT launched by I and IX Corps to regain territory south of Han River.
Jan-Feb 1stMarDiv continues antiguerrilla operations in Masan area.
  7 Feb Communists forced north of Han River. UNC retakes Inchon peninsula.
mid-Feb 1stMarDiv reassigned from X to IX Corps.
21 Feb Operation KILLER, a general limited objective advance by U.S. IX and X Corps, ordered by Gen Ridgway. 1stMarDiv reenters frontlines for operation.
  7 Mar Operation RIPPER begins in central and eastern zones, with advance across Han by IX and X Corps.
14 Mar Seoul retaken by U.S. Eighth Army for second time.
27–31 Mar 1stMarDiv occupies 28,000-meter sector north of Hongchon. UNC elements reach 38th Parallel.
  1–21 Apr 1stMarDiv in general advance north to the Hwachon Reservoir.
  8 Apr Operation RIPPER clears enemy troops from South Korea east of Imjin River.
11 Apr Pres Truman relieves Gen MacArthur as CinCUNC, replacing him by Gen Ridgway, CG, EUSAK. LtGen James A. Van Fleet named Commander, EUSAK.
15 Apr UNC establishes defensive line along 38th Parallel, or KANSAS Line. Enemy heavily emplaced in Chorwon-Kumhwa-Pyonggang (“The Iron Triangle”) assembly area.
22 Apr-8 Jul CCF launches all-out “Spring Offensive.”
23–27 Apr 1stMarDiv halts CCF left flank breakthrough of IX Corps, establishes defense line in Chunchon vicinity.
30 Apr UNC completes withdrawal to new defense line north of Seoul. Intelligence reports indicate CCF plans renewed attack.
  1 May 1stMarDiv reassigned to X Corps.
  9 May 1st MAW squadrons participate in FAF 300-plane strike on Sinuiju, near Yalu. Biggest raid of war to date.
16 May Second phase of enemy offensive begins. CCF drives south from Iron Triangle area, making penetrations 15–20 miles deep along the front.
20 May FAF launches Operation STRANGLE, massive all-out interdiction effort.
21 May UNC launches counter offensive, pushes enemy north of 38th Parallel again. 1stMarDiv drives toward Yanggu at eastern end of Hwachon Reservoir.
30 May Eighth Army back on KANSAS Line again.
  1–16 Jun 1stMarDiv advances northeast from Hwachon Reservoir to Punchbowl. Claws out daily gains of 1,000–2,000 meters, reaching objective despite heavy NKPA fire.
mid-Jun UNC forces consolidate positions at 38th Parallel. UNC front approximately the same line as when Communist spring offensive began.
23 Jun UN Soviet delegate, Jacob Malik, proposes cease-fire discussions.
30 Jun UN notifies enemy of its readiness to discuss an armistice.
10 Jul Truce talks begin at Kaesong and fighting dies down along front. UN delegation led by U.S. Vice Admiral C. Turner Joy. Communists represented by LtGen Nam Il, NKPA.
26 Jul Negotiators at Kaesong agree on preliminary agenda.
  5 Aug UNC suspends truce talks because of armed enemy troops in neutral area. Cease-fire talks resumed 10 Aug.
22 Aug Communists halt cease-fire talks, charge UN aircraft has violated neutrality zone.
31 Aug In final UNC offensive action of war, 1stMarDiv opens assault at Punchbowl. UN launches limited attacks to straighten line.
  5 Sep 1stMarDiv gains initial objectives in Punchbowl area, new ridgeline to become part of Line MINNESOTA, EUSAK defensive line. Heavy attacks by IX Corps at Heartbreak and Bloody Ridge.
13 Sep HMR-161 effects first Marine mass helicopter combat resupply maneuver, Operation WINDMILL I.
18 Sep Marines advance to Soyang River, north of Punchbowl.
21 Sep Operation SUMMIT, first helicopter deployment of a combat unit, lands 224 fully-equipped troops and 17,772 lbs of cargo in Punchbowl area.
25 Oct Following two weeks of discussion between liaison officers, truce talks resumed at new site, Panmunjom.
28 Oct Cease-fire line agreed upon as present line of contact.
11 Nov HMR-161 conducts first frontline relief of a Marine battalion, in Operation SWITCH.
12 Nov Gen Ridgway, CinCUNC, orders EUSAK Commander, Gen Van Fleet to cease offensive operations and begin active defense of UN front.
Nov-Dec General stalemate along Korean battlefront during truce discussions.
18 Dec Prisoner of war lists exchanged by UN and Communists.
1952
  2 Jan UNC proposes principle of “voluntary repatriation” in POW exchange.
  3 Jan UNC proposal violently rejected by Communists.
Jan-Apr Disorders in UNC prison camps as screening of prisoners begins.
22 Feb Communist Korean Foreign Affairs Minister charges America with renewed bacteriological warfare attacks in North Korea. Chinese Communist Foreign Minister Chou En-Lai, issues similar statement on 8 Mar, alleging U.S. flyers participate in “germ warfare.”
17 Mar 1stMarDiv reassigned from X Corps eastern-Korea position to I Corps far western end of EUSAK line. Takes over approximately 35 miles of Line JAMESTOWN on 24 Mar.
28 Apr Adm Joy presents UN “final offer,” insists on voluntary repatriation principle.
  7–11 May Rioting prisoners at Koje-do camp seize Gen Dodd and hold him hostage, until order restored.
12 May Gen Mark W. Clark succeeds Ridgway as CinCUNC, upon latter’s departure to assume NATO command from Gen Eisenhower.
22 May MajGen William K. Harrison succeeds Adm Joy as chief of UN delegation at Panmunjom.
Jun-Oct General stalemate along battlefront while truce talks deadlocked on POW repatriation question. Sharp limited objective attacks made by enemy against UNC defensive line.
  9–16 Aug First major Marine ground action in western Korea, Battle of Bunker Hill (1st Marines).
19–20 Aug HMR-161 Operation RIPPLE introduces tactical innovation of transporting 4.5-inch rocket battery weapons and personnel to new firing position.
29 Aug Largest one-day FAF air assault of entire war, “All United Nations Air Effort” sends 1,403 sorties against North Korean Capital, Pyongyang.
22–26 Sep First resupply of MLR regiment by helicopter in Operation HAYLIGHT.
  8 Oct UNC adjourns armistice talks “indefinitely”; complete deadlock on POW question.
26–28 Oct Battle of the Hook (7th Marines).
  4 Nov Dwight D. Eisenhower elected President.
17 Nov India introduces compromise truce plan at United Nations.
  2 Dec President-elect Eisenhower begins three-day tour of Korea.
  3 Dec UN General Assembly adopts compromise Indian resolution by 54 to 5 vote.
1953
Jan-Feb Winter lull in fighting. Cease-fire talks remain suspended.
  2 Feb President Eisenhower, in State of Union message, ends “neutralization” of Formosa Strait.
11 Feb Gen Maxwell D. Taylor assumes EUSAK command from Gen Van Fleet.
22 Feb UNC proposes exchange of sick and wounded POWs, as preliminary step in full exchange of prisoners.
  5 Mar Premier Joseph Stalin of Russia dies. Georgi Malenkov named to succeed him.
26–30 Mar 1stMarDiv combat outposts Vegas-Reno-Carson (5th Marines) under heavy attack.
28 Mar Communists accept UN proposal to discuss exchange of sick and wounded POWs.
30 Mar Chou En-lai indicates Communists will accept Indian UN compromise proposal. Truce talks to be resumed.
12 Apr 1st MAW flies first night CAS missions, using intersecting searchlight beams to mark enemy targets.
20–26 Apr Exchange of sick and wounded POWs, “Operation LITTLE SWITCH,” takes place at Panmunjom, under direction of Munsan-ni Provisional Command.
26 Apr Truce talks resumed at Panmunjom.
  5 May 1stMarDiv relieved by U.S. 25thInfDiv; 1st Division assigned mission of I Corps Reserve.
  7 May Communists accept UN proposal that prisoners unwilling to be repatriated be kept in neutral custody within Korea, rather than be removed elsewhere to a neutral nation.
28–30 May Savage fighting while truce details worked out by negotiators. CCF launches regimental-strength attack against I Corps sector. Heavy action in Nevada Cities and Hook area outposts. Marine tanks and artillery in support of defending 25thInfDiv line units.
  6 Jun ROK national Assembly demands freedom for anti-Communist North Koreans held in South Korean POW camps. Civilian demonstrations break out in various EUSAK and I Corps localities.
  8 Jun Agreement reached on POW question. POW nonrepatriates to be turned over to five-member neutral commission to decide disposition of POW cases. Pres Rhee declares armistice terms unacceptable to South Korea.
  9 Jun ROK National Assembly unanimously rejects truce terms.
10–17 Jun Communists launch heaviest offensive in two years against ROK II Corps sector in Kumsong area. Heavy penetrations, with ROK II Corps pushed 4000 yards south to new MLR.
18 Jun Breakout of 25,000 North Korean anti-Communist prisoners from South Korean POW camps, assisted by ROK guards. Release ordered by Pres Rhee as protest against proposed armistice.
18–20 Jun Communists accuse UNC of complicity in freeing prisoners; truce talks suspended.
23–25 Jun Pres Rhee continues opposition to truce terms. Walter Robinson, U.S. Asst. Sec. of State for Far East and Gen Mark Clark start confidential talks with Rhee.
  7–8 Jul COPs Berlin-East Berlin (7th Marines right regimental sector) under attack during Marine relief of 25thInfDiv.
  8 Jul 1stMarDiv assumes operational control of its former MLR sector, relieving 25thInfDiv.
  8 Jul Communists agree to resume armistice negotiations; talks reconvened 10 July.
11 Jul Robertson announces that Pres Rhee will no longer oppose truce terms.
11 Jul Maj John F. Bolt, VMF-115, becomes first Marine jet ace with kill of his fifth and sixth MIGs.
13–20 Jul CCF launches even larger offensive than June attack along central Korean front. IX and ROK II Corps MLR reestablished south of Kumsong River.
19 Jul Negotiators at Panmunjom reach agreement on truce.
19 Jul Marine outposts Berlin-East Berlin overrun; I Corps decrees positions should not be retaken.
24–27 Jul Heavy enemy attack in Berlin Complex (“Boulder City”) area held by 7th and 1st Marines.
27 Jul Cease-fire agreement signed at Panmunjom at 1000. Fighting ends. Armistice effective at 2200.
  5 Aug-6 Sep Final exchange of prisoners in Operation BIG SWITCH, at Panmunjom.