In Late May 1966 a force of 8,500 Marines and 2,500 South Vietnamese troops launched Operation Hastings. The goal of Operation Hastings was to thwart the efforts of the North Vietnamese 324 B Division to take control of Quang Tri Province.

The operation took place on the northeastern border of The Republic of South Vietnam.

Seven Marine infantry battalions deployed from Dong Ha, a small village south of the Demilitarized Zone, the boundary between North and South Vietnam. In support were elements of the U.S. Army, Air Force, Navy, and units of the Army of the Republic of Vietnam. The deployment of the Marine battalions was the largest and deepest penetration into South Vietnam since their arrival the previous year. The brushy hill country and tangled jungles in the mountains bordering the eastern DMZ was unexplored territory for American Infantry forces. The Marines moved north to engage forces of the North Vietnamese Army infiltrating south through this difficult terrain.

United States Marines were sent with a task organized Marine recon mission to pinpoint the location and activities of the North Vietnamese. Combined U.S. intelligence assets determined that a well equipped, superbly trained North Vietnamese force had massed in large numbers west of Dong Ha and south of the DMZ. The mission was successful.

Over the next ten days, the Marine Corps encountered its most bloody and bitter combat since the Korean War, fighting a jungle war that matched WWII in difficulty and savagery. Upon its conclusion, six of the seven Marine battalions were re-deployed, and the Operation was a declared a success. Press releases and "official sources" declared victory, reporting that the North Vietnamese Army fled back across the DMZ to sanctuaries in the north. The operation was one of the bloodiest, most difficult and historically significant battles of the war in Vietnam.