Thousands of years ago, the mammals of Southeast Asia, including the Asian elephant, Indochinese tiger, wild water buffalo, and Asian black bear, discovered the most efficient travel routes across Indochina’s Annamese Cordillera. These species also first located the mountain passes that later connected northern and central Vietnam with Laos and Cambodia; and they found the best places to ford the area’s boulder-strewn streams and rivers. By the nineteenth century, mammals had deepened and widened a few trails into veritable highways.
The ancient mammalian trail network through the Annamese Cordillera largely adhered to the contours of watersheds, with the widest, most-heavily-trodden routes following the flat terrain of the area’s biggest river valleys, while smaller trails traced the edges of streams and rivulets. However, there were exceptions to this general rule. For example, where high, steep valley walls pinched in on the bottomlands, trails exited the lowlands and ran across the tops of adjacent ridgelines or along the sides of nearby hills. And in open country, trails might dart off in every direction, without any discernible pattern. For instance, on the flatlands immediately east of the Chu Pong Massif, animals had created a chaotic system of trails through the understory.
When the Montagnards first entered the Annamese Cordillera after fleeing from the Han and Kinh/Viet padi states, they adopted the long-established mammalian trail network as their own.
In the late 1940s, French anthropologist Georges Condominas lived among the Mnong in the village of Sar Luk, forty kilometers northwest of Dalat. Condominas confirmed that Montagnard trails, like the older mammalian trails, followed the contours of watersheds. He wrote, “…the traditional paths that do connect villages are still the most heavily traveled. They are narrow, and whenever possible they run along valley floors….”
The ancient trail network within the cordillera determined where the Montagnards built their villages. Since the greatest number of mammals moved along paths that paralleled the region’s largest rivers, the Montagnards, not surprisingly, located their villages in those same river valleys.
Sar Luk occupied a prime piece of highlands real estate. It sat on a point of land between the Mei and Kroong rivers. Those two rivers not only provided village residents with fresh water and fish, but also with game animals that traipsed up and down the Mei and Kroong valleys. But that wasn’t all. Wild elephants trekked over those same river valley trails; and occasionally the Montagnards captured one of the big animals, tamed it, and then put it to work.
Sar Luk’s location also gave its residents the ability to control the ecologically-rich Mei and Upper Kroong river valleys. No other competing group of hunter-gatherers or swidden agriculturalists could access the resources of the Mei or Upper Kroong without first passing the Mnong stronghold at Sar Luk.
Montagnard trails and village sites played an important military role in the Vietnam War. Communist forces used segments of the ancient trail network to transport men and materials from North Vietnam into South Vietnam. Overtime, these infiltration routes became known collectively as the Ho Chi Minh Trail.
In the early and mid-1960s, U.S. Army Special Forces built dozens of outposts next to Montagnard villages in the Central Highlands of South Vietnam. These outposts, and the men stationed behind their fortifications, were supposed to interdict North Vietnamese and Vietcong troops entering South Vietnam. Unfortunately for the Americans, the large number of Montagnard trails, in conjunction with adverse weather, difficult terrain, and dense jungle, made it impossible for the Green Berets and their Montagnard allies to halt more than a fraction of Communist infiltration into South Vietnam.
 Georges Condominas, translated by Adrienne Foulke, We Have Eaten the Forest: The Story of a Montagnard Village in the Central Highlands of Vietnam, (New York: Hill and Wang, 1977), 5.
 Francis J. Kelly, Vietnam Studies, U.S. Army Special Forces, 1961-1971, (Washington, D.C.: Department of the Army, 2004), 50.