The beach at Riwŏn, shown with US troops landing. 1950
Riwŏn is mountainous, although there are also small plains, and is home to the Taedŏk Mountains (대덕산맥). The highest peak is Taedŏksan (1,442 m). There are some 10 significant streams; the chief of these is the Namdaech'ŏn, which drains into the Sea of Japan. There are various bays and islands along the coast. Thanks to its coastal location, the county enjoys a mild maritime climate. Forestland (70% of which is coniferous) takes up 73% of the county's area.