Except for the narrow piedmont coastal plains, the terrain of Quảng Trị province is dominated by hills and the Annamite Mountains.

The highlands, characterized by steep slopes, sharp crests, and narrow valleys, are covered mainly by a dense broadleaf evergreen forest.

The narrow coastal plains flanking the highlands on the east have rocky headlands and consist of belts of sand dunes and, in areas where the soil is suitable, paddy field.

From the crests that mark the drainage divide in the highlands, streams flow either east towards the South China Sea or west into Laos or Cambodia.

Those flowing eastward follow short courses through deep narrow valleys over rocky bottoms until they reach the coastal plains, where they slow down and disperse.

In the immediate prehistorical period, the lowlands of Quảng Trị and central Vietnam as a whole were occupied by Cham peoples (Champa), speaking a Malayo-Polynesian language, and culturally distinct from the Vietnamese to the north along the Red River.

In 1966, North Vietnamese forces (PAVN) also began occupying the northern region and pushing deeper into the province.

The provincial capital, Quảng Trị City, was overrun and occupied briefly by Communist troops in April 1967, and was a principal battleground during the 1968 Tet Offensive when it was again overrun by North Vietnamese troops and held for a short period before being recaptured by South Vietnamese government and U.S.