For organizational purposes , the Pacific Ocean is divided into three parts : the eastern ( North America to 140 W ) , central ( 140 W to the International Date Line ) , and western ( west of the Date Line ) . For organizational purposes , the northern Pacific Ocean is divided into three regions : the eastern , ( North America to 140 Â W ) , central ( 140 Â W to 180 Â ) , and western ( 180 Â to 100 Â ) .