Early in March, 1966, in Quang Ngai Province, South Vietnam, rifle companies from three under-strength Marine Corps battalions engaged elements of the 36th Infantry Regiment of the Peoples’ Vietnam Army. At first, the operation didn't even have a name. It became known as Operation Utah. The Marines prevailed, but at great cost.
For two days, not counting a two-day mopping up period, the Marines faced well-trained, well-armed enemy troops who had, over the previous several months, built and supplied a virtual underground fortress on and around a hillock known as Hill 50.
Among the combatants was the 3rd Battalion, 1st Marines. The Virtual Vietnam Archive contains this brief reference 3/1's part in Operation Utah; it's interesting to note how such military/bureaucratic scribblings hide so much blood and suffering:
Among the documents I have collected related to my tour of duty in South Vietnam is a copy of the "After-Action Report" signed by Col. J. R. Young, 3/1 Battalion Commander. Once you work through the military jargon and dispassionate reporting style, what emerges is a clear illustration of the bravery of both the Marines and the North Vietnamese troops, of poor military intelligence and planning, and of understated slaughter.
After-action reports are not always available for the Vietnam War. Some have simply disappeared, at least from public view. We veterans of Operation Utah are fortunate to have the "Operation Utah After-Action Report"
Another document held by the Virtual Vietnam Archive is an historical narrative of the events leading up to Operation Utah, of the operation itself, and of its aftermath. It is titled simply "Operation Utah".