301 Area Code is part of 10 counties in the state of Maryland. There are around 18 cities and 292 other places such as towns, cdps and villages in the 301 area code. Area code 301 is a telephone area code in the North American Numbering Plan (NANP) for the U.S. state of Maryland. Below you will find more info about Code and also zip codes, counties, cities and the post offices that belong to this Area Code.
Sources: North American Numbering Plan Administration (NANPA), telecom providers, and the U.S. Census Bureau.