Map 2 of Maps of SEA in the 1960s

Hanoi is approximately 700 miles from Saigon.  This is comparable to the distance between Washington, D.C. and St. Louis, Missouri—and about 100 miles more than the air distance between London and Berlin.

Hanoi had to maintain long supply lines to support its forces in South Vietnam.  Naturally, both sides focused on the most vulnerable sections of those lines of communications (LOCs).  In addition, the distances had to be considered in selecting locations for basing American aircraft.

The geographic boundaries and size of the region provided an additional factor that combined with political factors to further emphasize the military significance of the Laotian panhandle. South Vietnam's elongated shape had approximately 1,800 miles of seacoast and 900 miles of borders shared with North Vietnam, Laos, and Cambodia.   Borders of that length are virtually impossible to seal.  The topographical features of the region made the defense of South Vietnam against infiltration even more difficult.

The Chaine Annamitique, better known as the Annamite Mountains, stretches along most of Southeast Asia.  Rugged mountains cover the border between Laos and both North and South Vietnam.  The narrow, coastal plains of the Vietnams are east of the mountains, along the Gulf of Tonkin and the South China Sea.

Most of Laos is extremely rugged with some mountains rising to more than 9,000 feet.  The smoothest terrain are the lowlands near Vientiane and in the western half of the panhandle along the Mekong River, which separates Laos from Thailand.  Elevations in the plains of the Mekong basin are typically from 300 to 650 feet above sea level.