It was recaptured by UN forces in late September 1950 during the UN offensive that followed the Inchon landings and the breakout from the Pusan perimeter.

UN Forces abandoned the region in mid-December 1950, during the withdrawal following the Chinese People's Volunteer Army intervention in the war.

Following the breakdown of armistice negotiations in August 1951, the United Nations Command decided to launch a limited offensive in the late summer/early autumn to shorten and straighten sections of their lines, acquire better defensive terrain, and deny the enemy key vantage points from which they could observe and target UN positions.

The Yanggu War Memorial Hall (양구전쟁기념관) is located in Haean town.

The 4th Infiltration Tunnel and the Eulji Observatory are located in the hills north of Haean town.