Which 1965 battle was the first major engagement between US and North Vietnamese forces?

The first major engagement between U.S. and North Vietnamese forces was the Battle of Ia Drang, fought in South Vietnam’s Central Highlands in November 1965. The battle formed part of the larger Pleiku campaign near the Chu Pong Massif and Ia Drang Valley.

Ia Drang consisted chiefly of fighting at Landing Zone X-Ray from November 14 to 16 and at Landing Zone Albany on November 17. The U.S. 1st Cavalry Division used helicopters to move troops rapidly into battle, supported by artillery and air strikes. North Vietnamese regulars of the People's Army of Vietnam countered by closing to short range, limiting the Americans’ ability to use firepower safely.

The battle became a landmark for modern airmobile warfare and included the first tactical use of B-52 bombers in support of U.S. ground troops. Although the United States claimed a tactical victory based on enemy casualties, Ia Drang also demonstrated that North Vietnamese forces could withstand concentrated American firepower. The Battle of Khe Sanh occurred later, while Ap Bac involved South Vietnamese forces and the Viet Cong in 1963.