Khao Yai National Park is a national park in Thailand. It lies largely in Nakhon Ratchasima Province (Khorat), but also includes parts of Saraburi, Prachinburi and Nakhon Nayok provinces. It was the country's first national park, established on September 18, 1962. A major role in its establishment was done by Boonsong Lekakul, one of the 20th century's most famous conservationists in Thailand.
