The UN retreat from North Korea was the withdrawal of United Nations forces from North Korea that took place from 2–25 December 1950.
On 30 September Republic of Korea Army 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. Within one month UN forces were approaching the Yalu River prompting Chinese intervention in the war. Despite the initial attacks by the Chinese People's Volunteer Army in late October-early November, the 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 defeats by the PVA in the Battle of the Ch'ongch'on River and the Battle of Chosin Reservoir in eastern Korea, UN forces withdrew from North Korea completing their withdrawal on 25 December. UN forces then prepared new defensive lines above Seoul for an expected renewal of the PVA offensive.