city, seat (1846) of Wetzel county, northern West Virginia, U.S., on the Ohio River, (Ohio River) about 32 miles (51 km) southwest of Wheeling. Settled by Edward Doolin in 1780, it was later called Martin's Fort to honour Presley Martin, who bought the land and organized defense measures after Doolin was killed by Native Americans. The name was changed to Martinsville in 1838; “New” was added in 1846 to avoid confusion with Martinsville, Virginia.

The city's economy is based on the manufacture of chemicals, glass, and aluminum. The New Martinsville River Heritage Days and Regatta is an annual event held on the Ohio River. Inc. town, 1838; city, 1950. Pop. (1990) 6,705; (2000) 5,984.