In the first major engagement of the war between regular U.S. and North Vietnamese forces, elements of the 3rd Brigade, 1st Cavalry Division (Airmobile) fight a pitched battle with Communist main-force units in the Ia Drang Valley of the Central Highlands.

On this morning, Lt. Col. Harold G. Moore’s 1st Battalion, 7th Cavalry conducted a heliborne assault into Landing Zone X-Ray near the Chu Pong hills. Around noon, the North Vietnamese 33rd Regiment attacked the U.S. troopers. The fight continued all day and into the night. American soldiers received support from nearby artillery units and tactical air strikes. The next morning, the North Vietnamese 66th Regiment joined the attack against the U.S. unit. The fighting was bitter, but the tactical air strikes and artillery support took their toll on the enemy and enabled the 1st Cavalry troopers to hold on against repeated assaults.

At around noon, two reinforcing companies arrived and Colonel Moore put them to good use to assist his beleaguered soldiers. By the third day of the battle, the Americans had gained the upper hand. The three-day battle resulted in 834 North Vietnamese soldiers confirmed killed, and another 1,000 communist casualties were assumed.

In a related action during the same battle, 2nd Battalion, 7th Cavalry, was ambushed by North Vietnamese forces as it moved overland to Landing Zone Albany. Of the 500 men in the original column, 150 were killed and only 84 were able to return to immediate duty; Company C suffered 93 percent casualties, half of them deaths.

Despite these numbers, senior American officials in Saigon declared the Battle of the Ia Drang Valley a great victory. The battle was extremely important because it was the first significant contact between U.S. troops and North Vietnamese forces. The action demonstrated that the North Vietnamese were prepared to stand and fight major battles even though they might take serious casualties. Senior American military leaders concluded that U.S. forces could wreak significant damage on the communists in such battles–this tactic lead to a war of attrition as the U.S. forces tried to wear the communists down. The North Vietnamese also learned a valuable lesson during the battle: by keeping their combat troops physically close to U.S. positions, U.S. troops could not use artillery or air strikes without risking injury to American troops. This style of fighting became the North Vietnamese practice for the rest of the war.

The conflict was described by journalist Joe Galloway and retired Lt. Gen. Hal Moore in the 1992 book "We Were Soldiers Once ... And Young," which was later made into a film.