Area code 301 is an area code that covers Western Maryland, specifically the part of Maryland that is included in the Washington DC metro area. Area code 301 overlays the area code of 240.
Maryland has area codes of 227, 240, 301, 410, 443, 667.
The following map shows the coverage of 301 area code. The coverage area is shown in green.
Area code map of the entire U.S.