The northern part of Nakhon Nayok is located in the Dong Phaya Yen mountain range an area covered by the Khao Yai National Park. Yod Khao Kiew, its highest peak, is 1,292 meters above sea level. The central part of the province is on a contrary, a rather flat river plain formed by the Maenam Nakhon Nayok. The southern part of the province has relatively unfertile acidic soil.