Clarksburg was named in 1778 for General George Rogers Clark and incorporated in 1785. During the Civil War, it served as a supply depot of the Union Army from 1861 to 1865. General George B. McClellan had his headquarters here in 1861 until the Battle of Bull Run.
The first documented visitor to the area now known as Clarksburg was John Simpson, a trapper, who in 1764 located his camp on the West Fork River opposite the mouth of Elk Creek.
Clarksburg is the birthplace of General Thomas J. Stonewall Jackson. Although Clarksburg is remembered for the birthplace of Stonewall Jackson, most families of Clarksburg were on the union side of the American Civil War.