The province is located at the valley of the river Mekong and is mostly plain. In the northern part of the province has more upland character, and forest covered plains. The main river in the northern part is the Songkhram River and the smaller Oun river. The southern part is more flat, and has the Kum river as only notable river. The provincial capital, the city of Nakhon Phanom, is located directly at the banks of the Mekong.
Phu Lang Ka National Park covers 50 km of forests and hills, and includes the waterfalls Tat Kham and Tat Pho as its most popular attractions. Also flowers like the Lady Slipper Orchid and diverse wildlife is found in the park.