Leatherneck Square was an area just south of the Vietnamese DMZ.

It was cornered by Con Thien

Con Thien

Con Thien , was a United States Marine Corps combat base located near the Vietnamese Demilitarized Zone about 3 km from North Vietnam...

 to Gio Linh

Gio Linh

Gio Linh is a rural district of Quang Tri province in the North Central Coastal region of Vietnam. Gio Linh borders Vinh Linh to the north, Dong Ha to the south. The planned Quang Tri Airport will be constructed in this district. As of 2003 the district had a population of . The district covers...

 in the north, about 6 miles (9.7 km) wide (east to west) and from Dong Ha

Dong Ha

Đông Hà is the capital town of Quang Tri province, Vietnam. It is located at around . Dong Ha is situated at the crossroads of National Highway 1A and Route 9, part of the East-West Economic Corridor . It lies on the Reunification Express Railway and is served by Dong Ha Railway Station...

 to Cam Lo

Cam Lo

Cam Lộ is a rural district of Quang Tri province in the North Central Coastal region of Vietnam. As of 2003 the district had a population of 46,231. The district covers an area of 347 km²...

 in the south. The length of this square was about 9 miles (north to south).

Some of the heaviest fighting of the Vietnam War

Vietnam War

The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...

was fought in this 54+ square mile area.