1966 in the Vietnam War

January
Operation Crimp also known as the Battle of the Ho Bo Woods—was a joint US-Australian military operation during the Vietnam War in the Ho Bo Woods, 20 km north of Cu Chi in Binh Duong Province, South Vietnam, between 8–14 January 1966.
 * January 8–14

Operation Masher was a combined U.S., ARVN, and ROKA operation that began on January 28, 1966. The name "Operation Masher" was changed to "Operation White Wing", because the name was deemed too crude for 'nation-building'.
 * January 28 – March 6

February
The Battle of Suoi Bong Trang was a major action during the Vietnam War fought on the night of 23–24 February 1966 between US and Australian troops, and the Viet Cong and North Vietnamese Army. The battle occurred during Operation Rolling Stone, a major American security operation to protect engineers building a tactically important road in the vicinity of Tan Bihn, in central Binh Duong Province, 30 km northwest of Bien Hoa airbase.
 * February 23–24

March
The Battle of A Shau was waged in 1966 during the Vietnam War between the North Vietnamese Army and the forces of the United States and South Vietnam. The battle began on March 9 and lasted until March 10 with the fall of the special forces camp of the same name. The battle was an outright victory for the North Vietnamese; it was nevertheless a costly battle that U.S. estimates suggest cost the attackers almost half of their force.
 * March 9–10

April
The Battle of Xa Cam My was a battle of the Vietnam War fought over two days from April 11 to April 12, 1966. Originally planned as a U.S. search and destroy mission intended to lure out the "crack" Viet Cong D800 Battalion, Charlie Company soon found itself fighting for survival in the rubber plantations of Xa Cam My, approximately 42 miles (68 km) east of Saigon. During this battle 134 men of Charlie Company, 2nd Battalion, 16th Infantry, 1st Infantry Division were ambushed by the Viet Cong.
 * April 11-April 12

Operation Birmingham was a military operation of the Vietnam War in War Zone C, north of Saigon. The US 1st Infantry Division and the ARVN 5th Division conducted operations on the eastern flank of War Zone C. The goals were opening Route 13 from Saigon to the north and engaging the Viet Cong 9th Division. The Viet Cong suffered heavy losses, but managed to withdraw beyond the Cambodian border. Operation Beaver Cage was a U.S. Marine Corps and U.S. Navy Joint Operation in North Vietnam along the coastline of the Bon Hai river in the Quang Nam province. The Operation took place 23 August 1966, through 5 September 1966.
 * April 24 to May 17
 * April 28–May 12, 1967

July
Operation Hastings was attempt to by the Americans to engage enemy troops in the Cam Lo area, on July 7, 1966, United States Marine Corps General Lew Walt led a joint U.S. Marine and ARVN force of 8,500 and 3,000 troops in a strike through the Demilitarized Zone (DMZ). Plans to maintain U.S. occupation of the Cam Lo area in the Quang Tri province soon became known as Operation Hastings.
 * July 7 –Aug 3

August

 * Aug 3 to Oct 27, 1966

Operation Prairie (Aug 3 - Oct 27, 1966) was a military operation in northern South Vietnam. Its job was to eliminating North Vietnamese Army forces south of the DMZ. Battle of Đức Cơ was a major engagement between the North Vietnamese 5th Battalion of the 33rd Regiment and the South Korean 3rd Battalion of the 1st Cavalry Regiment on August 9, 1966. The battle resulted from North Vietnamese attempts to infiltrate Đức Cơ from Cambodia. The Battle of Long Tan was fought between the Australian Army and Viet Cong forces in a rubber plantation near the village of Long Tần, about twenty seven kilometres north east of Vung Tau, South Vietnam on 18 August 1966. It is arguably the most famous battle fought by the Australian Army during the Vietnam War.
 * August 9, 1966
 * August 18, 1966

September
Operation Attleboro was a search and destroy operation by the 196th Light Infantry Brigade. The operation was named after Attleboro, Massachusetts, where the brigade had been formed. The Philippine Army deployed to Vietnam.
 * September 14–November 24
 * September 14