Arnoldsburg (also Arnoldsburgh) is an unincorporated community in Calhoun County, West Virginia, United States. It lies along U.S. Route 33 at the point where West Virginia Route 16 heads southward, to the south of the town of Grantsville, the county seat of Calhoun County. Its elevation is 738 feet (225 m). Although it is unincorporated, it has a post office, with the ZIP code of 25234.