The Headquarters and adjacent Visitor Center of the circa 738 kmē Khao Sok National Park, a rainforest with a 165 kmē lake and towering karst formations in Surat Thani, is located at Khlong Sok in Phanom District.

The nature reserve is a natural habitat of the Rafflesia (fig.), a giant parasitic flower that attaches itself to the nutrient system of woody lianas and can grow to a diameter of up to a meter. This world's largest single flower is the park's emblem.