Trying to simplify things the best, there were 3 major theater of operations during Vietnam:
-The Demilitarized Zone and the northern provinces of Quang Tri (Khe Sanh, Rockpile, Con Thien) and Thua Thien (A Shau, Song Bo, Street without Joy, Hué)
-The Highlands (Pleiku and Kontum provinces mainly with such battlefields as the Ia Drang, Se Sanh, Nam Sathay and Plei Trap valleys and the Dak To area)
-The Saigon region (Iron Triangle, War Zones C and D, Rung Sat, Route 13...)
That's where most of the fighting occured. Three other areas saw prolonged confrontation too but were of slightly lesser importance:
-Southern I CTZ between Da Nang and Quang Ngai
-The Central Coast between Qui Nonh and Cam Ranh Bay
-The Mekong Delta (IV Corps)
