Tesso Nilo National Park, National park in Riau, Indonesia

Tesso Nilo National Park is a lowland rainforest in Riau Province, Sumatra, first designated in 2004 at about 38,576 hectares and expanded in 2009 to roughly 83,068 hectares. A 200 m2 plot was found to hold 218 vascular plant species, and surveys recorded at least 360 flora species, 107 birds, 50 fish, 23 mammals, 18 amphibians, 15 reptiles and 3 primates.

The park was established in 2004 to protect one of Sumatra's last remaining lowland rainforests from widespread cutting. It was created during a critical time when this forest region faced intense pressure from human development.

The park's name comes from the Tesso and Nilo rivers that cross the forest area. Nine ecotourism trails are used for walking, cycling, canoeing and camping, and trained elephants are part of the permitted activities. The surrounding landscape is shared with 23 villages spread across four regencies: Kampar, Pelalawan, Indragiri Hulu and Kuantan Singingi.

Visitors should organize their trip and arrange guided tours with specialists to observe wildlife like elephants, tigers, and birds. The best time to visit is during the dry season when trails are easier to walk and animal sightings happen more often.

In 2011 Belgium pledged 200,000 euros for a Sumatran elephant conservation centre here, funding the transfer of tame elephants from Minas in Siak district, where oil palm plantations and oil mining had destroyed their habitat. A 2012 count based on dung samples put the park's population at 120 to 150 elephants.