The park was declared a reserve in 1964 and on 12 June 1981, it became the 28th national park of Thailand. Originally covering an area of 1,548,750 rai ~ , it was enlarged in December 1984 to include the boundary area between Phetchaburi and Prachuap Khiri Khan Provinces, an additional 273,125 rai ~ . The park has been included on the list of
ASEAN Heritage Parks. It is part of the
Kaeng Krachan Forest Complex, which the Thai government had repeatedly nominated for designation as a
World Heritage Site since 2011. At its 2019 meeting, UNESCO's World Heritage Committee (WHC) rejected Thailand's third bid, citing outdated information regarding boundaries and a lack of local community participation. In July 2021 Thailand made its fourth application for World Heritage Site recognition. On 26 July 2021, the 21 nations of the UNESCO World Heritage Committee voted 12–9 to approve Kaeng Krachan's listing as a World Heritage Site. with authorities unable to control poachers. Some park officials are allegedly involved in the trade of elephant parts. Despite national park status, there are private plantations within the confines of Kaeng Krachan National Park. Some of these are surrounded by
electric fences which, in June 2013, fatally electrocuted an elephant calf. In 2018, the park started taking bids on a project to pave 18.5 kilometres of the Bang Krang to Phanoen Thung Road. It is budgeted at 87.62 million
baht. The existing one-lane dirt road is "broken beyond repair" according to the park's chief. Environmentalists oppose the project on the grounds that easier accessibility will mean more tourists in the fragile ecosystem. The park chief says, "...the project does not violate regulations...and [we have] a duty...to proceed with the project." The project was halted, at least temporarily, in early-November 2018 by the National Parks Department to allow opponents to be heard on the issue. ==Flora and fauna==