Ang Ka Luang

The Ang Ka Luang boardwalk loops through Thailand’s highest-altitude peat bog, at roughly 2,550 metres near the summit of Doi Inthanon. The wet core of the bog covers about 30 rai (4.8 hectares) and holds water year-round, thick with sphagnum moss — a species that needs constant cool moisture and only grows at this kind of altitude in Thailand — along with algae and moss coating the tree trunks and branches. Mist hangs over the boardwalk for much of the day, especially in the cool season.

Michael MacMillan Walls, a Canadian zoologist who volunteered at Doi Inthanon National Park, surveyed and built the original trail between 1991 and 1993. He died of a heart attack while working at the site — a piece of the trail’s history that park staff and local guides still pass on. The boardwalk was renovated in 2021 by the EGCO Group, the Thai Forest Conservation Foundation, and the national park department, replacing worn sections of timber to keep visitors off the fragile bog surface.

Insider Tip: Ang Ka Luang gets far fewer visitors than the nearby Kew Mae Pan trail, despite being an easier, shorter walk — worth the short detour if you want the cloud forest without the crowds.

The loop itself is short, somewhere between 300 and 360 metres depending on the source, and entirely flat since it runs on a raised boardwalk. Fifteen to twenty minutes covers it at an easy pace. There’s no separate entry fee — access is included in the standard Doi Inthanon park entrance ticket.

Watch out: Temperatures at this altitude can sit well below what you’d expect from a Chiang Mai forecast, even in April. Bring a jacket regardless of season, and stay on the boardwalk — the bog surface it protects is easily damaged by foot traffic.

Kew Mae Pan Nature Trail, the longer ridge-walk nearby, is the natural pairing for the same visit. For the rest of the park and the wider area, see Chiang Mai.

Getting There

Ang Ka Luang is located at Mae Chaem, Chiang Mai. View on Google Maps.