Kaeng Krachan National Park is the biggest national park of Thailand, covering 2,914 sq km in the districts of Nong Ya Plong, Kaeng Krachan and Tha Yang in Phetchaburi Province, and Hua Hin district of Prachuap Khiri Khan Province.
Kaeng Krachan National Park is the source of two major rivers, the Pranburi River and the Phetchaburi River. The highest point in the park is 1200 meters above sea level. There is a dam built here in 1966 across the Phetchaburi River, creating a 46.5 sq km reservoir.
Kaeng Krachan National Park was established on 12 June, 1981 with an original size of 2,478 sq km, as the 28th national park of Thailand. It was subsequently enlarged on 27 December, 1984.