Battle of Chosin Reservoir A map illustrates the path of United Nations troops during the Battle of Chosin Reservoir, Dec. 6-11, 1950. Approximately 30,000 U.N. troops began to break out of the Chosin Reservoir area in a fighting withdrawal to the Port of Hungnam on the Sea of Japan to join the U.S. Eighth Army defending the 38th parallel. SHARE: Download: Full Size (0.11 MB) Credit: Courtesy photo VIRIN: 141218-F-BN648-007A.JPG Photo Gallery