Kayan Mentarang National Park, National park in North Kalimantan, Indonesia.

Kayan Mentarang National Park is a protected forest reserve in North Kalimantan covering mountainous terrain with river valleys. The park's landscape includes dense forests, water systems, and elevated regions with various ecosystems.

Archaeological remains like stone tools and burial sites within the park show that humans have lived in this region for a very long time. These discoveries provide evidence of early settlement and occupation of the area.

Indigenous Dayak communities live around the park's borders, maintaining their traditional ways in forest villages. You can observe how they interact with the land and forest resources in daily life.

Entry is possible from Malaysia via Ba'kelalan in Sarawak, where agreements under the Heart of Borneo initiative allow tourist movement into the park. The park stretches along the Malaysian border and is reached mainly by river; at Long Aran on the Bahau, boats up to 20 metres long are hauled by hand when the water is low. Local Dayak boatmen navigate the rapids.

The park's name comes from two rivers, the Kayan in the south and the Mentarang in the north; another account traces it to the broad Apau Kayan plateau stretching from Datadian through Apau Ping to Long Bawan. In the Pujungan district the sun is said never to rise or set, hidden by cloud, yet its glare burns skin without felt heat.