 During the North Koreans ' September 1 offensive , the US 25th Infantry Division 's US 35th Infantry Regiment was heavily engaged in the Battle of Nam River north of Masan . On the 35th Regiment 's right flank , just north of the confluence of the Nam River and the Naktong River , was the US 9th Infantry Regiment , US 2nd Infantry Division . There , in the southernmost part of the 2nd Infantry Division zone , the 9th Infantry Regiment held a sector more than 20 @,@ 000 yards ( 18 @,@ 000 m ) long , including the bulge area of the Naktong where the First Battle of Naktong Bulge had taken place earlier in August . Each US infantry company on the river line here had a front of 3 @,@ 000 feet ( 910 m ) to 4 @,@ 000 feet ( 1 @,@ 200 m ) and they held only key hills and observation points , as the units were extremely spread out along the wide front . 
