Doi Khun Tan National Park

Doi Khun Tan National Park straddles the ridge between Chiang Mai and Lamphun provinces, with the park’s highest point reaching 1,373 metres. It’s best known for sitting directly above Thailand’s longest railway tunnel — the Khun Tan Tunnel, 1,352 metres of the Northern Line running beneath the pass — but the tunnel itself is working rail infrastructure, not something you walk through. Trains still pass daily, so it’s a ride-through, not a hike-through.

The park is reached by train: Khun Tan station sits inside the park boundary, and from there trails climb through teak and mixed deciduous forest to a series of viewpoints along the ridge. Wildlife sightings depend on timing and patience — barking deer and macaques turn up in quieter forest sections, and the mixed forest is known locally as decent birding ground, hornbills included. Orchids bloom along the trails during the cool season (November-February), which is also when the ridge gets genuinely cold at night.

Insider Tip: Ride the train to Khun Tan station rather than trying to drive — there’s no road into the park headquarters, and the train journey through the tunnel is part of the experience most visitors come for.

A basic campsite near the ranger station is the only overnight option inside the park; tents can be rented on site, but bring warm layers regardless of season, since the elevation drops the temperature well below what you’d expect in the lowlands nearby. Watch out: the tunnel walkway is off-limits and patrolled — it’s an active mainline, not a pedestrian trail, whatever older travel write-ups suggest.

Trails are unguided and manageable without a park ranger, though a map from the visitor centre near Khun Tan station helps on the ridge sections where signage thins out. Entry costs 100 THB for foreign adults (50 THB for children) and 20 THB for Thai adults (10 THB for children), under the Department of National Parks’ standard fee schedule in force since June 2022.