West Virginia currently utilizes 2 area codes. When first established by AT&T and the Bell System in 1947, 304 covered the entire state of West Virginia. The most recently added was 681 in 2009 as an overlay to 304. Today, 304 is the most populated with an estimated 1.9 million of the state's 1.9 million residents.
Sources: North American Numbering Plan Administration (NANPA), telecom providers, and the U.S. Census Bureau.