Military units and formations of the United States in the Vietnam War

U.S. Military Assistance Command, Vietnam (MACV) was a joint-service command of the United States Department of Defense.

Tiger Force was the nickname of a Long-range reconnaissance patrol unit of the 1st Battalion (Airborne), 327th Infantry Regiment, 1st Brigade (Separate), 101st Airborne Division, which fought in the Vietnam War.

The 23rd Infantry Division, more commonly known as the Americal Division, of the United States Army was activated 27 May 1942 on the island of New Caledonia.

The 4th Infantry Division is a division of the United States Army based at Fort Carson, Colorado.

The 1st Cavalry Division ("First Team") is a combined arms division and is one of the most decorated combat divisions of the United States Army, as well as the other four branches of the U.

The 82nd Airborne Division is an airborne infantry division of the United States Army, specializing in parachute assault operations into denied areas.

The 1st Infantry Division is a combined arms division of the United States Army, and is the oldest continuously serving in the Regular Army.

The 173rd Airborne Brigade Combat Team ("Sky Soldiers") is an airborne infantry brigade combat team of the United States Army based in Vicenza, Italy.

The 25th Infantry Division (nicknamed "Tropic Lightning", "Electric Strawberry", and the "Củ Chi National Guard" during the Vietnam War) is a U.

The 5th Infantry Division (Mechanized)—nicknamed the "Red Diamond", the "Red Devils", or "die Roten Teufel"—was an infantry division of the United States Army that served in World War I, World War II and the Vietnam War, and with NATO and the U.

The 2nd Infantry Division ("Indianhead") ("2ID," "2nd ID" or "Second D") is a formation of the United States Army.

Military Assistance Command, Vietnam – Studies and Observations Group (MACV-SOG) was a highly classified, multi-service United States special operations unit which conducted covert unconventional warfare operations prior to and during the Vietnam War.

A Hatchet Force or Hatchet Team was a special operations team of American and South Vietnamese members of MACV-SOG during the Vietnam War, who operated in small covert operations along the Ho Chi Minh trail from 1966.

HA(L)-3, (Helicopter Attack Squadron (Light) 3), nicknamed the “Seawolves”, was an all-volunteer US Navy squadron formed in support of Naval Special Warfare operations and Mobile Riverine Forces during the Vietnam War.