Shortly before the Pusan Perimeter battles began, Walker established Taegu as the Eighth Army's headquarters. Right at the center of the Pusan Perimeter, Taegu stood at the entrance to the Naktong River valley, an area where KPA forces could advance in large numbers in close support. The natural barriers provided by the Naktong River to the south and the mountainous terrain to the north converged around Taegu, which was also the major transportation hub and last major South Korean city aside from Pusan itself to remain in UN hands. From south to north, the city was defended by the US 1st Cavalry Division, and the ROK 1st and 6th Divisions of ROK II Corps. 1st Cavalry Division was spread out along a long line along the Naktong River to the south, with its 5th and 8th Cavalry Regiments holding a line along the river and the 7th Cavalry Regiment in reserve along with artillery forces, ready to reinforce anywhere a crossing could be attempted.