Khao Nan National Park is 30 kilometres from Amphoe Tha Sala. The park covers areas in Amphoe Tha Sala, Amphoe Sichon and King Amphoe Nop Phitam. In addition, the park has areas in Pa Khao Nan National Forest Reserve and Pa Krung Ching National Forest Reserve. The total area of the park is 436 square kilometres. The main topography is a high mountain range extending from Khao Luang National Park. The park itself is a watershed of many waterways. From the city, travel by Highway No. 401 across Khlong Klai, and past Ban Sa Kaeo in Amphoe Tha Sala. Upon reaching the 110-km marker, turn left into Ban Pak Chao and drive 15 kilometres to the park office.