{"id":1086,"date":"2025-06-18T09:54:01","date_gmt":"2025-06-18T02:54:01","guid":{"rendered":"https:\/\/mocnam.vn\/abandoned-valley\/"},"modified":"2026-04-02T20:43:33","modified_gmt":"2026-04-02T13:43:33","slug":"abandoned-valley","status":"publish","type":"page","link":"https:\/\/mocnam.vn\/en\/abandoned-valley\/","title":{"rendered":"Abandoned Valley"},"content":{"rendered":"

<\/b>Abandoned Valley: 2,000-Hectare Wilderness Exclusively Operated by Moc Nam<\/span><\/b><\/h1><\/div>\n

Abandoned Valley sits deep inside the core zone of Phong Nha-Ke Bang National Park \u2014 a 2,000-hectare stretch of primary rainforest that most visitors to Phong Nha have never heard of. No roads lead in. No phone signal reaches it. Just limestone karst, ancient jungle, clear streams, and cave systems that have been forming for over 450 million years.<\/p>\n

Moc Nam Adventure is the only licensed operator in this area. No other company can bring you here.<\/p>\n

\"Abandoned<\/p>\n

Abandoned Valley \u2014 2,000 hectares of primary rainforest in the core zone of Phong Nha-Ke Bang National Park<\/figcaption><\/figure>\n

1. What is Abandoned Valley?<\/h2>\n

Abandoned Valley \u2014 known locally as Thung L\u0169ng Sinh T\u1ed3n \u2014 is a large mountain valley in the core zone of Phong Nha-Ke Bang National Park, in Quang Tri province (formerly Quang Binh). The starting point is Km17 or Km19 on the Western Ho Chi Minh Road.<\/p>\n

The terrain is classic karst transition: high limestone massifs surround the valley on all sides, with steep cliffs dropping into the valley floor. Elevation within the area ranges from 10 to 400 metres. The entire zone sits below 800m, fed by water converging from multiple directions.<\/p>\n

Where does the name “Abandoned Valley” come from?<\/h3>\n

According to local history, the A Rem ethnic minority once lived here \u2014 hunting, gathering, sheltering in cave systems, and trading with the outside world. Over time, due to war and increasingly difficult conditions, they relocated to flatter land better suited to community life. The name Abandoned Valley \u2014 Thung L\u0169ng B\u1ecf Hoang in Vietnamese \u2014 refers to that departure, leaving behind a landscape that has remained almost entirely untouched ever since.<\/p>\n

2. Geology and Formation<\/h2>\n

The cave systems inside Abandoned Valley formed over more than 450 million years of geological activity, beginning in the Paleozoic Era (Ordovician period onwards). The area sits across five geological formations \u2014 Dong Tho, Cat Dang, La Khe, Bac Son, and Mu Gia \u2014 creating an unusually diverse geological profile that includes limestone karst, sedimentary sandstone, and clay mountains.<\/p>\n

One detail that sets this valley apart: all the water emerging at E Cave’s entrance belongs to the Phong Nha river system \u2014 fed by underground streams from Son Doong Cave, the largest cave on earth. The flow originates near Ban Khe Rung at 570m elevation close to the Vietnam\u2013Laos border, travels approximately 35km underground through the Son Doong, Nuoc Nut, and Tra Ang cave systems, then resurfaces at E Cave before passing through Dark Cave Exit and joining the Chay River. Tre Stream \u2014 the surface waterway connecting E Cave to Dark Cave Exit \u2014 runs nearly 2km and forms the ecological spine of the entire valley.<\/p>\n

\"Tre<\/p>\n

Tre Stream \u2014 the waterway connecting E Cave and Dark Cave Exit, fed by the Son Doong underground river system<\/figcaption><\/figure>\n

3. Ecosystem<\/h2>\n

Three-canopy forest<\/h3>\n

The forest inside Abandoned Valley is classified as humid tropical evergreen closed-canopy rainforest \u2014 a protected special-use forest within the National Park’s core zone, structured across three distinct canopy layers:<\/p>\n

Upper canopy:<\/strong> Large hardwoods with trunk diameters of 30\u201370cm dominate \u2014 most notably the Dracontomelon duperreanum (S\u1ea5u), an ancient giant so wide it takes 8 to 10 people joining hands to encircle the trunk. These trees break through the main canopy to form the highest layer of the forest.<\/p>\n

Mid canopy:<\/strong> Dense and layered, populated with Garcinia, Scaphium, and species from the Euphorbiaceae, Rutaceae, and Lauraceae families.<\/p>\n

Ground layer:<\/strong> Thrives in moist microsites \u2014 Impatiens, Gesneriaceae species, and leafy shade plants covering the forest floor.<\/p>\n

The valley is also home to the largest area of bamboo and rattan in Phong Nha-Ke Bang National Park, concentrated in the Tre Valley (Thung Tre) section \u2014 the reason locals once simply called this place “Bamboo Valley.”<\/p>\n

Rare plant species<\/h3>\n

A specialist survey recorded 142 plant species across 63 families in the area. Among them: three species listed in Vietnam’s Red Book (Drynaria fortunei, Gynostemma pentaphyllum, and Garcinia oblongifolia); one species under Decree 32 on endangered plant management (Fibraurea tinctoria); and six species on the IUCN Red List, including Diplazium esculentum, Rothmannia cambodiana, Cassia ferruginea, Knema globularia, Knema pierrei, and Madhuca pasquieri.<\/p>\n

Wildlife<\/h3>\n

The valley supports 100 recorded animal species \u2014 36 aquatic, 14 reptiles, 38 amphibians, 4 mammals, and 8 birds. Five species appear in the Red Books:<\/p>\n