Kwaksan County is a kun (Korean: 군; Hanja: 郡, 'county') in coastal southern North P'yŏngan province, North Korea. It faces the Yellow Sea to the south. By land, it is bordered by Kusŏng city to the north, Chŏngju to the east, and Sŏnch'ŏn to the west.

Numerous small rivers meet the sea in Kwaksan, including the Tongrae, Sasŏng, and Sach'ŏn (사천강). There are 15 islands off the coast, which measures 67 kilometres (42 mi) in total. Forestland occupies 46.5% of the county's area, and is 80% pine; cultivated land occupies 30% of the area, and is 50% rice paddies.

Kwaksan county is divided into 1 ŭp (town) and 19 ri (villages):

The year-round average temperature is 9.2 °C (48.6 °F), with a January mean of −8.2 °C (17.2 °F) and an August average of 23.7 °C (74.7 °F). The average annual rainfall is 1,380 millimetres (54 in).

The chief crops are rice, maize, apples, and peaches. Silkworms and livestock are also raised, and fishing also contributes to the local economy.

The P'yŏngŭi Line of the Korean State Railway passes through the county on its way between P'yŏngyang and Sinŭiju.

Local attractions include a five-story stone pagoda dating from the Koryŏ period in Wŏnha-ri, and the Rŭngsan fortress (릉산성), established in 996 by the general Sŏ Hŭi.

The only institution of higher learning in the county is a technical school.