Tham Hong is located in Ban Pithum Moo 3, Krung Ching Subdistrict, Nopphithum District, Nakhon Si Thammarat. The cave is composed of fascinating stalactites and stalagmites. This cave was discovered in 1994 in the area of Khao Nan National Park. The stream flows through the cave before flowing underground to the stream outside the cave. There are stalactites and stalagmites with different shapes. Inside the cave, there is a waterfall with over 5 levels. To visit the cave, you have to walk along the stream about 300 meters. The cave is a bat inhabitant and also suitable for learning the origin of stones. During a rainy season, there is a great flood which is not suitable for tourism. This cave is called “Tham Hong” (Cave of the Swan) after the folktale of a hunter finding a swan inside the cave while hunting in the wood.