The Hyeongsan River is a river in southeastern South Korea. It flows from Baeyanggol Valley (배양골), Wolpyeong-ri (월평리/), Dudong-myeon (두동면/), Ulju County in Ulsan to the Sea of Japan (East Sea), covering a distance of about 62 km. The Hyeongsan watershed covers roughly 1,167 km² (Jo 1987:35).