Phu Hin Rong Kla National Park has an area of 307 square kilometers.
It lies in Dansai district of Loei province and Nakhon Thai district of Phitsanulok province. Phu Hin Rong Kla is blessed with natural beauty and historical significance. From 1968 to 1972, the mountains of Phu Hin Rong Kla were the majorstrongholds for the communists, who were threatening the political stability of the nation. In 1982, government forces began the battle in Phu Khang, and attempt to drive out the insurgents. The government forces were unsuccessful,primarily because of the unforgiving terrain, set high up in the mountains in mostly dense forest. Now the battels are long over, and the geologied features landscape and natural beauty in the area have been restored and protected after the communist insurgents loss.
The general topography of the park is steeply mountainous. The northern part of the park in Chaiburi Dstrict borders Laos. The Southern part of the park runs into Phetchabun Province. The mountain range includes the peaks of Phu Phangma, Phu Lomlo, Phu Hin Rong Kla and Phu Man Khao, the tallest in the park at 1,820 meters above sea level. The second tallest is Phu Lomlo at 1,664 meters. The park is the headwaters of many streams, including Huai Mueat Don, and Huai Luang Yai.
(http://www.thailandtraveltours.com/phu-hin-rong-kla-national-park.htm)