It borders Nyŏngbyŏn on the west, Hyangsan and Unsan counties on the north, Nyŏngwŏn on the east, and Kaech'ŏn and Tŏkch'ŏn cities to the south.

Kujang county is divided into 1 ŭp (town), 5 rodongjagu (workers' districts) and 22 ri (villages): The average annual temperature is 8.4 °C, with a January mean of -10.4 °C and an August mean of 24.2 °C.

The caves in the Kujang area are karstic grottoes formed during the Quaternary of the Cenozoic Era in limestone formations.

Despite similar origins, they vary in size, scope, and aesthetic features due to karstic evolution.

Ryongmun Cavern, located 370 meters above sea level, stretches 7 km with stalagmites and stalactites.