Khao Chakan Arboretum

Khao Chakan Arboretum is a 488-rai forest reserve wrapped around the three limestone peaks of Khao Chakan — Khao Chakan itself in the centre, Khao Ming to one side, Khao Fha to the other — about 20 km from Sa Kaeo town via Highway 317. It’s free to enter, managed since 1980 by the Forest and Plant Conservation Research Office rather than run as a paid attraction, and the real draw isn’t above ground: it’s what’s cut into the hillside.

The mountain holds roughly 72 limestone caves of varying size. Tham Muet (Dark Cave) lives up to its name — no natural light reaches the back chambers, so a torch matters. Tham Khao Thaolu runs straight through the rock and opens at both ends, letting you see daylight from inside. Others — Tham Hanuman (Monkey Cave), Tham Maha Hing, Tham Nam Thip, Tham Kaew Phlai Chumpol — each have their own chamber shapes and local names tied to old stories about the mountain. Alongside the caves, the reserve still carries the dipterocarp forest and limestone-adapted scrub typical of an Isaan foothill, with the usual soundtrack of cicadas and the odd hornbill overhead.

The arboretum shares its hillside with Wat Tham Khao Chakan, a Mahayana Buddhist temple whose main hall — poured in reinforced concrete in 1890 — sits at the base. From the temple grounds, roughly 300 steps climb to a summit viewpoint over the surrounding plain. The temple itself is catalogued separately on this site as Wat Tum Khao Chakan — worth combining with the arboretum since they’re the same mountain but different management and different focus (nature reserve vs. working temple).

Watch out: Cave floors are uneven and some passages are low — flip-flops aren’t enough. Bats roost in the darker caves, and their guano makes footing slippery near the entrances.

Insider Tip: Bring your own torch even if you plan to stick to the lit sections — Tham Muet’s back chamber is genuinely pitch black, and the temple doesn’t always have spare lights on hand.

There’s no formal gate or fixed opening hours; the reserve is open through daylight hours, and cooler months (November-February) make the exposed 300-step climb far more comfortable than the hot season. Bring water, insect repellent, and shoes with grip — a car or motorbike from Sa Kaeo town is the practical way in, since there’s no direct public transport to the site.