Niah National Park, about 110 km south of Miri (roughly three hours by road), contains one of the most important archaeological sites in Southeast Asia. Excavations of the Niah Caves between 1954 and 1967 uncovered human remains, tools, and animal bones spanning 40,000 years of continuous occupation — at the time, among the oldest evidence of modern humans in the region.
The Great Cave has a mouth 150 metres wide and 75 metres high, large enough to feel like a cathedral made of limestone. Inside, a plank walkway leads through the cave complex, past ancient paintings in the Painted Cave, and through passages where local collectors still harvest edible birds' nests twice a year using bamboo poles in near-darkness. The cave ceilings are thick with swiftlets and bats; the smell and sound are memorable. A 3.5 km jungle trek leads from the park entrance to the cave mouth through lowland dipterocarp forest.
Niah is accessible by bus from Miri or by taxi; there is basic accommodation near the park entrance.