Nam Nao National Park is a protected area in Phetchabun Province in northern Thailand. The park is a large forest filled with pineries, grasslands, and jungle. The park is home to approximately 360 species of birds and 340 species of butterflies. The average annual temperature is 25 degrees Celsius (77°F). Between December and January temperatures drop to as low as 2-5 degrees Celsius (36-41°F). Nam Nao National Park is part of a Level I "tiger conservation unit" (TCU). It encompasses 1,000 square kilometres (390 sq mi).

Phetchabun is one of Thailand's seventy-six provinces (changwat) lies in lower northern Thailand. Neighbouring provinces are Loei, Khon Kaen, Chaiyaphum, Lopburi, Nakhon Sawan, Phichit and Phitsanulok.