Khun Dan Dam was built according to the King’s project. The King had royally given the name of the dam as Khun Dan Prakan Chon Dam to honor the bravery of Khun Han Phithak Phraiwan or Khun Dan, the hero of Nakhon Nayok in the Ayutthaya era. The dam is 2,720 meters long, 93 meters high and can contain water for 224 million cubic meters. It receives the water that flows from Khao Yai National Park through Heo Narok Waterfall into the reservoir. It can prevent flooding and reduce the damage from overflowing. It is a new tourist attraction of Nakhon Nayok in which you can see the view of Khao Yai National Park from the ridge of the dam and see the landscape of Mueang Nakhon Nayok from behind the dam.