Tazewell County (/tæz.wɛl/) is a county located in the southwestern portion of the U.S. state of Virginia. As of the 2010 census, the population was 40,429. Its county seat is Tazewell. Tazewell County is part of the Bluefield, WV-VA Micropolitan Statistical Area. Its economy was dependent on coal and iron of the Pocahontas Fields from the late 19th into the 20th century.