The UN Forces retreat from North Korea was the withdrawal of United Nations (UN) and Republic of Korea Army (ROKA) forces from North Korea that took place from 2–25 December 1950.
On 30 September 1950 ROKA forces crossed the 38th Parallel, the de facto border between North and South Korea on the east coast of the Korean peninsula and this was followed by a general UN offensive into North Korea to pursue the shattered North Korean Korean People's Army (KPA). Within one month ROKA/UN forces were approaching the Yalu River prompting Chinese intervention in the war. Despite the initial attacks by the Chinese People's Volunteer Army (PVA) in late October-early November, the ROKA/UN renewed their offensive on 24 November before it was abruptly halted by massive Chinese intervention in the Second Phase Offensive starting on 25 November. Following their defeat by the PVA at the Battle of the Ch'ongch'on River and tactical withdrawal at the Battle of Chosin Reservoir, ROKA/UN forces evacuated North Korea in its entirety on 25 December. ROKA/UN forces then prepared new defensive lines above Seoul for an expected renewal of the PVA offensive. The withdrawal from North Korea included many migrations of refugees fleeing from Chinese and North Korean forces that quickly recaptured North Korea. Two notable mass refugee escapes from North Korea include the Hungnam evacuation and the evacuation of Pyongyang.
Background On the night of 28 November UN commander General Douglas MacArthur met with US Eighth Army commander General Walton Walker and US X Corps commander General Edward Almond in Tokyo to assess the position of UN forces. Having received updates from his ground commanders, MacArthur judged that the Eighth Army was in greater danger than the X Corps, but he wanted both commands to step back. Walker was to make whatever withdrawals were necessary to escape being enveloped. Almond was to maintain contact with the PVA but also was to pull X Corps back and concentrate it in the Hamhung-Hungnam coastal area. MacArthur next asked Almond what X Corps could do to help the Eighth Army. Almond pointed out that the isolated Marine and Army troops at the Chosin Reservoir had to be retrieved before anything else could be done.
Eighth Army front Following their victory in the Battle of the Ch'ongch'on River, the PVA did not pursue the US Eighth Army's withdrawal from the Ch'ongch'on to the Sukch'on-Sunch'on-Songch'on line. Only light PVA patrolling occurred along the new line on 1 December, mostly at its eastern end where there had been no deep withdrawal the day before. Walker nevertheless believed that the PVA would soon close the gap, resume their frontal assaults, and again send forces against his east flank. Walker now estimated the PVA opposing him to number at least six armies with 18 divisions and 165,000 men. Of his own forward units, only the US 1st Cavalry Division, 24th and 25th Infantry Divisions, the ROKA 1st Infantry Division and the British 27th Commonwealth Brigade and 29th Independent Infantry Brigade were intact. The ROKA 6th Infantry Division could be employed as a division, but its regiments were tattered; about half the ROKA 7th and 8th Infantry Divisions had reassembled but were far less able than their strengths indicated; and both the 2nd Infantry Division and Turkish Brigade needed substantial refurbishing before they could again function as units. Of his reserves, the four ROKA divisions operating against guerrillas in central and southern Korea were too untrained to be trustworthy on the line. His only other reserves were the 187th Airborne Regimental Combat Team and its attached Filipino and Thai battalions then guarding forward army supply installations; the Netherlands Battalion, which had just completed its processing at the UN Reception Center; and an infantry battalion from France, which had just disembarked at Pusan.
By Walker's comparison of forces, the injured Eighth Army could not now set a successful, static defense. Considering delaying action to be the only course open, a course in which he should not risk becoming heavily engaged and in which he should anticipate moving out of North Korea, Walker began to select delaying lines behind him. He intended to move south from one to the next well before his forces could be fixed, flanked, or enveloped. Though Eighth Army remained out of contact on 2 December, Walker received agent and aerial observer reports that the PVA were moving into the region east of Songch’on and that either they or North Korean guerrillas infesting that area had established blocking positions below the Pyongyang-Wonsan road from Songch’on eastward miles to Yangdok. They could be trying to secure a portion of the lateral route in advance of a drive toward either or both coasts, and should the drive go west into Pyongyang, they could trap the Eighth Army above the city. In view of the latter possibility, Walker elected to withdraw before the thrust materialized. Pyongyang was to be abandoned. Walker's use of relatively slight intelligence information in deciding to withdraw below Pyongyang reflected the general attitude of the Eighth Army. According to some accounts, Walker's forces had become afflicted with "bugout fever," a term usually used to describe a tendency to withdraw without fighting and even to disregard orders. Because it implied cowardice and dereliction of duty, the term was unwarranted. Yet the hard attacks and high casualties of the past week and the apparent Chinese strength had shaken the Eighth Army's confidence. This same doubt had some influence on Walker's decision to give up Pyongyang and would manifest itself again in other decisions to withdraw. But the principal reason for withdrawing had been, was, and would continue to be the constant threat of envelopment from the east.
X Corps front In order to protect Hamhung and Hungnam while the 1st Marine Division and Army units withdrew from the Chosin Reservoir, in early December Almond was concentrating his forces there. Meanwhile, at Wonsan a 3rd Infantry Division task force and United States Marine Corps shore party group was to protect that area, load the supplies and equipment stockpiled there and then abandon the area. By nightfall on 4 December, 3rd Infantry Division commander General Robert H. Soule concentrated the bulk of his division in the Hamhung-Hungnam area. With the 1st Korean Marine Corps Regiment attached, he deployed on the 5th to defend a sector anchored below Yonpo Airfield southwest of Hungnam and arching northwest through Chigyong southwest of Hamhung to the village of Oro-ri () on the Chosin Reservoir road northwest of Hamhung. By dark on the 5th the greater part of the 7th Infantry Division also reached the Hamhung-Hungnam area. To assist the 7th's evacuation of Hyesanjin, the attached ROKA 26th Regiment had taken covering positions astride the main Hyesanjin-Pukch’ong withdrawal route about midway between the terminal towns. But the 7th Division came south without enemy contact. They demolished bridges and cratered the road behind them as far as the ROKA position and in continuing their withdrawal prepared similar demolitions to be exploded by the ROKA bringing up the rear. The 7th Division forces, after completing their withdrawal, put up defenses north and northeast of Hamhung adjacent to those of the 3rd Division. The leftmost position was not far east of Oro-ri, astride the road leading south from the Pujon Reservoir (); the rightmost blocked the coastal road. The 7th Division block at the right was temporary. Almond's plan for ringing Hamhung and Hungnam now called for ROKA I Corps to hold the northeast sector, including the coastal road. But the nearest ROKA I Corps troops were still up the coast at Songjin, the rearmost another north in Kilchu. To assist the ROKA withdrawal, Almond arranged on the 5th through Admiral James H. Doyle to send five ships to Songjin to pick up the tail-end ROKA 3rd Infantry Division. The ROKA I Corps headquarters and the Capital Division meanwhile continued to withdraw overland.
Retreat Eighth Army withdrawal below Pyongyang As Walker started his withdrawal from the Sukch'on-Sunch'on-Song-ch'on line on 2 December, Major general Doyle O. Hickey, acting chief of staff of the Far East Command and UN Command, arrived with word from MacArthur that, in effect, allowed Walker to leave behind any equipment and other materiel that he chose as long as they were destroyed. Walker, however, planned not to drop behind Pyongyang until the army and air force supply points in the city had been emptied and the port of Chinnamp'o cleared. To provide time for the removal he ordered a half step to the rear, sending his forces south toward a semicircular line still above Pyongyang. While service troops rushed to evacuate supplies and equipment from the North Korean capital and port, line units reached the temporary line late on 3 December with no PVA interference beyond being harassed by North Korean guerrillas on the east flank. Walker meanwhile pushed reserves eastward onto Route 33, the next Pyongyang-Seoul road inland from Route 1, to protect his east flank and to guarantee an additional withdrawal route below Pyongyang. He deployed the 24th Infantry Division at Yul-li (), southeast of Pyongyang, and the partially restored ROKA II Corps at Sin'gye in the Yesong River valley another to the southeast. South and east of Sin'gye, units of the ROKA 2nd and 5th Infantry Divisions previously had occupied Sibyon-ni () and Yonch'on on Route 33, P’och’on on Route 3, and Ch'unch'on on Route 17 in the Pukhan River valley during anti-guerrilla operations. Route 33 thus was protected at important road junctions, and Walker at least had the semblance of an east flank screen all the way from Pyongyang to Seoul. Walker moved the damaged US 2nd Infantry Division from Chunghwa into army reserve at Munsan-ni on the Imjin River north of Seoul, where General Laurence B. Keiser, with priority on replacements, was to rebuild his unit. But while Keiser's immediate and main task was to revive the 2nd Division, Walker wanted him also to reconnoiter as far as Hwach'on, more than east of Munsan-ni, in case it became necessary to employ 2nd Division troops in those areas guarded by ROKA units of doubtful ability. Walker attached the Turkish Brigade to the 2nd Division. Hurt less by casualties than by disorganization and equipment losses, the Turks had collected bit by bit at several locations, mostly at Pyongyang. On 2 December, after General Yazıcı had recovered some 3,500 of his original 5,000 men, Walker ordered the brigade to Kaesong, north of Munsan-ni, to complete refurbishing under Keiser's supervision as more of its members were located and returned. Walker held the 187th Airborne Regimental Combat Team and its attachments in the Pyongyang area to protect his supply routes and installations. In preparation for the coming withdrawal south of the city, the airborne troops also were to keep civilians from moving over four pontoon bridges spanning the Taedong River, two inside Pyongyang and another pair east of the city, and to take whatever other precautions were necessary to insure an uninterrupted flow of military traffic over the crossings.