The province, in the Mekong River valley, is mostly plains. The northern part of the province has a more upland, forest-covered character. The main river in the northern part is the Songkhram River with the smaller Oun River. The southern part is flatter with the Kum River as its only notable watercourse. The provincial capital, the city of Nakhon Phanom, is on the banks of the Mekong.