Phu Toei national park is located in the north-western tip of Suphanburi province. Inside the park boundary of 317 square kilometers are waterfalls, caves, river streams, hills covered with dry and moist evergreen forests. The highest peak is Khao Thewada at 1123 meters, which is bordering with the Thailand's western forest. Merkus pine forest exist at elevation of about 750 to 800 meters in the park.