This is the fourth volume of a chronology of Marine Corps activities which cover the history of the U. S. Marines. It is derived from unclassified official records and suitable published contemporary works. This chronology is published for the information of all interested in Marine Corps activities during the period 1965-1969 and is dedicated to those Marines who participated in the events listed. This chronology was produced as a ready reference to Marine Corps activities during 1965-1969 when the United States was deeply involved in the war in Vietnam. Through out this chronology, geographic locations are used to introduce each entry to enable the reader to locate the event with greater ease. The heading "USMC" is used when an event affected the Marine Corps in its entirety."