Ninety kilometres north of Vientiane, the vast Ang Nam Ngum Reservoir sits above the northern edge of the Vientiane Plain, where the rice-growing flatlands surrounding the capital meet the mountainous terrain of the north. Created when the Nam Ngum River was dammed in 1971, the deep green waters of the reservoir are dotted with scores of forest-clad islands stretching to a dramatic horizon lined with mountains, their peaks lost in mist. Foreign travellers, usually in a rush to head upcountry, tend to bypass Ang Nam Ngum as they make for nearby Vang Vieng, but those who do stop off discover a pretty 250-square-kilometre expanse of water with islands, secluded beaches and swimming spots. There are a number of convenient options for visiting Ang Nam Ngum, either as a day-trip from Vientiane or Vang Vieng or en route between the two; short package trips are also available from travel agents in Vientiane.

Built with foreign expertise and funding, the reservoir is the driving force behind Laos’s production of hydroelectricity – the country’s largest export earner until the late 1980s – and provides power for Vientiane and surrounding villages on the Vientiane Plain. Most of the power, however, flows across the Mekong into Thailand, which has an agreement to purchase Laos’s surplus electricity. The reservoir is also slowly being developed for tourism and boasts a huge hotel on the southern shoreline, the DanSaVanh Nam Ngum Resort (, complete with casino, golf courses and a marina. Less brash is Longngum View Resort (, on the western shore of the lake, which has bungalows and rooms with good views of the water.

At the time the dam was built, the Royalist government had only just plugged Vientiane into the hydroelectric dam before they were forced to cede power to the communist Pathet Lao. In an all too typical example of poor environmental planning, the builders of the dam had flooded a vast area of valuable forest 50m underwater. The rotting vegetation sucked oxygen out of the water and blocked up the turbines, a problem that was later turned into profit by underwater logging ventures, whose frogmen dropped to the reservoir floor to cut submerged trees with underwater saws. Meanwhile, the new communist government found a novel use for the reservoir. After 1975, prostitutes, thieves and teenagers “infected with foreign ideas” were rounded up from the streets of Vientiane, a Lao Sodom in the eyes of the Pathet Lao, and were confined on islands in the middle of the lake for “re-education”.

These days, day-tripping Lao head for Ang Nam Ngum with relaxation in mind, descending on the scenic reservoir in droves at weekends and hiring out wooden boats for picnic cruises. If you visit, you’ll find good swimming, peaceful sandy beaches, and floating restaurants serving fresh seafood dishes just above the water. Fishing is actually one of the main industries at the reservoir, but most of the catch is sold in the markets of Vientiane.

Reaching the reservoir

Getting to Ang Nam Ngum by public transport is easy enough. From Vientiane, four government buses depart daily from the bus station near the morning market for Thalat (there are also more frequent sawngthaews here, leaving from the stand in front of the bus station). From Thalat, you can get a shared tuk-tuk to the reservoir (30 min; $5) or the regular tuk-tuk shuttle service to Na Nam, near the dam on the western shore of the reservoir, and the most logical base for independent travellers to explore the lake by chartering a taxi ($25 return). If you go for this option, you might consider making a scenic detour en route along the quieter Route 10 via Ban Keun. Southbound sawngthaews from Vang Vieng pass right by the town of Tha Hua at the northern end of the reservoir, or you can switch vehicles at the Phonhong junction and cut in to Thalat and Na Nam. If you want to use the lake as an alternative route from Vientiane north to Vang Vieng, charter a boat from Na Nam for the five-hour trip to Tha Hua and then continue by road to Vang Vieng.

Travel companies offer one- to three-day package tours to the reservoir out of Vang Vieng, which combine hiking, boating and camping, but expect to pay considerably more for the convenience. You can usually arrange a private boat trip on the reservoir by asking around in Na Nam. Guesthouses and hotels mentioned here should also be able to point you in the direction of the best hiking trails.

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