Phetchabun is located in central Thailand, in the broad fertile river valley of the Pa Sak River. The Phetchabun mountain range lies to the east and west. It has several national parks along the border, while the center is fertile agricultural land.
Nam Nao National Park is noted for various caves. The longest caves are around 10 km long, one of the caves is a popular show cave.
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Phetchabun Province - Wikipedia
Nam Nao National Park | Caves & Caving in Thailand
National Park of Thailand, Online Reservation National Park of Thailand, Forest Park of Thailand, Thailand National Park, Thailand Forest Park, Wildlife and Plant Conservation Department, Royal Forest Department
The Caves of Phetchabun Province