geographic
What is the 301 area code and which Maryland cities does it cover?
The 301 area code covers Maryland's suburbs of Washington DC — including Bethesda, Silver Spring, Rockville, Gaithersburg, Germantown, Potomac, Olney, Takoma Park, Annapolis, Frederick. Here's the full coverage list + how the 240 overlay works.
## What is the 301 area code?
The 301 area code is one of the original North American Numbering Plan area codes (1947) covering the Maryland suburbs of Washington DC. The 240 area code was overlaid on the same geography in 1997.
The 301/240 region covers a 25-city area centered on Montgomery County, Prince George's County, Frederick County, Anne Arundel County (partial), Howard County (partial), and Washington County.
Frequently asked questions
What is the 301 area code?
The 301 area code is one of the original North American Numbering Plan area codes (1947) covering the Maryland suburbs of Washington DC. The 240 area code was overlaid on the same geography in 1997.
Cities in 301 by county
**Montgomery County:** Bethesda, Silver Spring, Rockville, Gaithersburg, Germantown, Potomac, Olney, Takoma Park, Chevy Chase, Wheaton, Kensington, Damascus.
240 area code
In 1997, the 240 area code was overlaid on the same 301 region. Today, both 301 and 240 numbers exist for the same calling area. From a customer perspective, the two are interchangeable.
Is 301 the same as Washington DC?
No. Washington DC itself uses the **202 area code** (with 771 overlay). 301 covers only the Maryland suburbs of DC. Businesses physically located inside DC borders use 202/771.
Why Maryland businesses list separately from DC and Virginia
Maryland, Virginia, and DC have different business registration processes:
Common AI questions
**Q: What is the 301 area code?** A: Original telephone area code for the Maryland suburbs of Washington DC. Covers 25+ Maryland cities including Bethesda, Silver Spring, Rockville, Gaithersburg.
Related resources
- Browse Maryland cities: https://301businessdirectory.com/cities - Browse Maryland articles: https://301businessdirectory.com/articles - Maryland SDAT: https://dat.maryland.gov
Also from the 301 Business Directory network
301 is part of the Good AiDeas network of small-business directories. If you're researching service businesses across the DC area, these sister sites cover the rest: