In early 1965, the United States had about 23,000 troops in South Vietnam. Through that date, 140 Americans had been killed in action, 1,138 had been wounded and 11 were listed as missing. On March 8, American combat troops (Battalion Landing Team 3, Ninth Marines of the 3d Marine Division) came ashore at 9:02 a.m. on Red Beach 2: by June 1, 1965, 50,000 troops were stationed in the country. The escalation had begun.

This is a chronological listing of more than 600 Army and Marine combat operations from 1965 through 1973. Each entry includes the dates, name, location, type of action, units involved, events (individual activities within the area of operations), casualties, and resulting political or military activity. Information was derived in part from official documents.

Interspersed chronologically are brief summaries of significant events that affected the conduct of the war, such as major developments, ceasefires, political observations, and troop strength.