There are abundant mountains, with the Ch'ŏnma and Munsu ranges both traversing the county.

The highest peak is Ch'ŏnmasan, 1169 m. The Ch'ŏnmasan region provides habitat for a variety of animals, and has been designated an animal protection area.

The county lies in the Yalu River basin; major tributaries draining the county include the Samgyoch'ŏn and the Kojin and Ch'ŏnma Rivers; these have been dammed to create Manp'ung Lake as well as the Taeha Reservoir, the water from which is used to water the plains along the Yellow Sea.

Ch'ŏnma county is divided into 1 ŭp (town) and 20 ri (villages): The climate is continental, with hot summers and cold winters.

Chonma leads the province in the production of hops.