[1]: 142  The new Lancaster TAOR bordered the Vietnamese Demilitarized Zone (DMZ) to the north, the Scotland TAOR to the west and the Kentucky and Operationa Osceola to the east and contained the Marines bases of Camp Carroll, The Rockpile and Ca Lu Combat Base and was under the control of COL Joseph Lo Prete's 3rd Marine Regiment.

[2]: 18  Despite the closure of Route 9 by the People's Army of Vietnam (PAVN) west of Ca Lu, it remained the obvious route for any attempt to relieve the Khe Sanh Combat Base.

The terrain in the Lancaster TAOR consisted of rolling hills climbing up to jungle-covered mountains.

[2]: 57 The Marines task was to prevent PAVN infiltration from across the DMZ and from the west and to provide artillery and logistical support to the Marines at Khe Sanh.

[2]: 57 This article incorporates public domain material from websites or documents of the United States Marine Corps.