To support the Marine attack towards Mupyong-ni, Hagaru-ri became an important supply dump with an airfield under construction. Smith and 1st Marine Division headquarters were also located at Hagaru-ri. With the bulk of the 1st Marine Division gathered at Yudam-ni, Hagaru-ri was lightly defended by two battalions from the 1st and 7th Marines, the rest of the garrison being composed of engineers and rear support units from both the Army and the Marine Corps.