The economy of Mason County was diverse and flourishing by the mid-19th century. Abundant timber supported a boat yard at Letart and a later shipbuilding industry at Mason and Point Pleasant. Sand and gravel quarries, oil and natural gas wells, and coal mines were developed. Mining began in West Columbia (where George Washington had seen a ‘‘coal hill on fire’’) in 1847 and neighboring Clifton in 1853. Mining continued until the 1960s. In the 1850s and late 1860s, entrepreneurs from Connecticut founded the towns of New Haven and Hartford in the Pomeroy Bend area. The city of Mason was incorporated in 1856. These three towns became centers of a booming new industry based on salt brine. At Mason, Dr. H. Stieren of St. Louis established a bromine factory in 1868 which became the largest producer of bromine in the world. A Mason County native, Michael J. Owens (1859–1923), invented a bottle-making machine and became a key figure in the American glass industry. The State Hospital for the Colored Insane and the State Industrial School for Colored Boys were established at Lakin in 1923.
Industry continued to develop through the 20th century, the products including polyester resins, plastic film, TNT, synthetic hydraulic lubricants, metal alloys, malleable iron casting, furniture, dresses, and ceramic insulators. Marietta Manufacturing Company began an operation at Point Pleasant in 1915 and produced small ocean-going craft during World War II. The electric power industry became a major employer after World War II with the construction of the Philip Sporn plant at Graham Station and the Mountaineer plant at New Haven.
River commerce has been important throughout the county’s history. The Gallipolis Locks and Dam was constructed in 1933–37. One of the largest such facilities in the world when built, it has since been replaced by the Robert C. Byrd Locks and Dam.
Information from: https://www.wvencyclopedia.org/articles/1563