Gamaksan (Korean: 감악산), also known as Kamak Mountain or Hill 675 (675고지) during the Korean War,[1] is a mountain in Gyeonggi Province, South Korea.

Its sits between the cities of Paju, Yangju and Yeoncheon County.

According to the Annals of King Taejo, during the Joseon dynasty, the royal court held a byeolgieun on this mountain in spring and autumn.

Since the Three Kingdoms period it has been a battleground: Battles were fought here during the Khitan invasion, and it was also the main battlefield of the Battle of Gorangpo during the Korean War.

Being on the border of the demilitarised zone (DMZ) there continue to be military bases closeby.