The UN forces established a perimeter around the port city of Pusan throughout July and August 1950. Roughly long, the perimeter stretched from the Korea Strait to the Sea of Japan west and north of Pusan. To the west the perimeter was roughly outlined by the Naktong River where it curved at the city of Taegu, except for the southernmost where the Naktong turned eastward after its confluence with the Nam River. The northern boundary was an irregular line that ran through the mountains from above Waegwan and Andong to Yongdok.