301 Area Code
Western Maryland (suburban DC), Maryland
Area code 301 is located in Western Maryland (suburban DC), Maryland. It covers Silver Spring, Rockville, and surrounding areas in the Eastern time zone (UTC-5). Administered by NANPA.
Where is area code 301?
Area code 301 is located in Western Maryland (suburban DC), Maryland. It covers Silver Spring, Rockville, and surrounding areas in the Eastern time zone (UTC-5).
Area code 301 is overlaid by area code 240. Both codes serve the same geographic region and require 10-digit dialing for local calls.
Cities Covered by Area Code 301
Area code 301 primarily serves the Western Maryland (suburban DC) area of Maryland. The exact coverage includes Silver Spring, Rockville, and Bethesda, along with surrounding communities and suburbs.
Time Zone
Eastern Time — UTC-5
Area code 301 operates in the Eastern Time Zone. When calling 301 numbers from a different time zone, be sure to account for the time difference to reach people during business hours.
About Area Code 301
Area code 301 was introduced in 1947 as a geographic area code serving Western Maryland (suburban DC), Maryland. As demand for phone numbers grew, overlay code 240 was added to the same region, requiring 10-digit dialing for local calls. Area codes are administered by NANPA (North American Numbering Plan Administration), the organization responsible for managing phone number resources in the US and Canada.