Located in the Eastern (GMT -05:00) time zone. Area code 304 serves the state of West Virginia. This area code was assigned on January 1st, 1947. On January 1st, 1947 it went into service. 304 is a General Purpose Code. 304 service area does overlap with 681 area codes. Dialing pattern for local calls within the same NPA (area code) is 10D.