Khao Nan National Park (อุทยานแห่งชาติเขานัน) is 30km from Amphoe Tha Sala. The park covers areas in Amphoe Tha Sala, Amphoe Sichon and King Amphoe Nop Phitam. The main topography is a high mountain range extending from Khao Luang National Park. The park itself is a watershed of many waterways.
The park’s main attraction is Sunantha waterfall which is a small but lovely waterfall. Water drops down a steep cliff to the pool below before flowing into Khlong Klai, the main waterway of Tha Sala. Rafting can be done in the canal when the water level is high.