Tham Singha is an important civilization attraction of Udon Thani. It is an ecological tourist spot with ancient paintings of 2,300 years, located in the area of Khon Yun Subdistrict, Kut Chap District, Udon Thani.

- Tham Singha contains all the paintings with red color called Pictograph, such as drawing, coloring, spraying, etc. It consists of two types of paintings: Figure, a painting with a fixed and clear shape such as animals and palms; and Non-Figure, a painting with an unstable shape such as geometric patterns.
- Lan Tub Kwai is a rocky shed like a large roof with wild plants around. In the past, the villagers brought cattle and buffaloes to rest and feeding. That is an origin of the name “Lan Tub Kwai”.
- Tham Khok Ma is a cave with overlapping sheds and a hollow allowing visitors to pass through. This cave is called Tham Khok Ma due to the correspondence with the story of 'Usa - Baros, a folktale of the north eastern people. That is, Thao Baros was looking for Usa and bound his horse around this area.
- Tham Rue Sri is a rocky cave with a height of 2.20 meters. There is a walkway with an overlapping rocky shed. There are also other interesting places as Naga Pond, Tham Sahai Kebsabieng, Lad Khom, Lad Khanoi, Menorah Pond, etc. "

Tham Singha is the name which the villagers called after the painting of a four-foot animal that resembles a lion image. In 2001, it was announced the discovery of paintings aged approximately 2,300 years, to Khon Yun Subdistrict Administrative Organization. The Khon Yueng Subdistrict Administrative Organization then informed the Education Office of Kut Chap District and the official survey was held on 14 and 22 September 2001.

The cave is 45 kilometres from Udon Thani City. Take Highway No.2263 (Udon Thani-Kut Chap route) passing Muban Nong Khong, Nong Charoen, and Nong Mek. Turn left at the T-junction of Wat Charoen Sattha Samakkhi to the Phu Lon Sangha monk's residence. Go on for around 3 kilometres to the foot of the Phu Phan Mountains and walks for another 3 kilometres.