Phu Phan National Park has won the Green National Parks award for outstanding environmental management, setting a new standard for a plant and animal habitat as well as a tourist attraction.
It is ranked top among 14 national parks that have passed new grading criteria designed to encourage park officials to better take care of forests, National Park Office chief Songtham Suksawang said.
"It earned a mark of 97.66%," he said, adding all 14 parks earned scores of 85% or higher.
A total of 17 were picked for this year's competition.
Judging criteria included how well officials deal with the impact of visitors, Mr Songtham said.
Sound garbage and wastewater management is also needed to ensure sustainable forest management, he added.
Phu Phan National Park spans 664 sq km in the two northeastern provinces of Sakon Nakhon and Kalasin. Tourists flock there for its waterfalls and caves. Historically, it served as a weapons cache for Japanese soldiers during World War II.
The other 13 national parks that were awarded for showing how wild spaces can coexist in harmony with tourism are, in order of the marks they received: Khao Sok in Surat Thani, Doi Phu Nang in Phayao, Khao Khitchakut in Chanthaburi, Chae Son in Lampang, Khao Sam Roi Yot in Prachuap Khiri Khan, Than Bok Khorani in Krabi, Inthanon in Chiang Mai, Doi Phu Kha in Nan, Pha Hom Pok in Chiang Mai, Khuean Krinagarindra in Kanchanaburi, Doi Luang in Chiang Rai, Tat Ton in Chaiyaphum and Ao Phangnga in Phangnga.