Operation Thayer

Operation Thayer (13 September 1966 – 1 October 1966), Operation Irving (2 October 1966 – 24 October 1966) and Operation Thayer II (24 October 1966 – 11 February 1967) were related operations with the objective of eliminating People's Army of Vietnam (PAVN) and Viet Cong (VC) influence in Bình Định Province on the central coast of South Vietnam. The operations were carried out primarily by the United States (US) 1st Cavalry Division against PAVN and VC regiments believed to be in Bình Định. South Korean and Army of the Republic of Vietnam (ARVN) forces also took part in the operation.

The sustained operations were deemed a success by the US, which claimed that more than 2,500 PAVN/VC killed at a loss of about 329 American dead. Many areas under PAVN/VC influence were abandoned by the rural population as non-combatants fled the fighting or were forced by American and South Vietnamese forces to leave their homes. The PAVN/VC were able to break up into smaller units and evade open-battle against an overwhelming air-land-sea deployment of US forces, and much like in Operation Masher which preceded it, they were able to return and contest the region once the operation had died down.