Arnoldsburg 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; it is several miles south of the county seat of Grantsville. Its elevation is 738 feet. The West Fork Little Kanawha River flows through the community. Although it is unincorporated, it has a post office, with the ZIP code of 25234.Arnoldsburg derives its name from Charles Arnold, a local schoolteacher.