Clarksburg is a city in and the county seat of Harrison County, West Virginia, United States, in the north-central region of the state. The population of the city was 16,578 at the 2010 census.

It is the principal city of the Clarksburg, WV Micropolitan Statistical Area, which had a population of 89,718 in 2019.

Clarksburg’s economy—formerly based on coal mining, oil and natural-gas production, and agriculture—has shifted more toward light manufactures and services. A significant addition to the regional economy is the Federal Bureau of Investigation’s large fingerprint-identification facility, which opened in 1995. A branch campus of Fairmont State College is in Clarksburg. In Salem, just to the west, is Salem-Teikyo University (chartered in 1888 as Salem College), which was created in 1989 as part of the Teikyo University Group of Japan. Watters Smith Memorial State Park is also nearby. Inc. city, 1921. Pop. (2000) 16,743; (2010) 16,578.