Maryland · Eastern Time
301 Area Code
The 301 area code is a telephone area code in Maryland, covering Frederick and the surrounding area. It lies in the Eastern Time zone.
Last updated June 5, 2026
Where is the 301 area code?
301 serves Frederick and nearby communities in Maryland. In the wider directory it sits in the South region.
Overlay codes serving Frederick
Frederick is served by an overlay of 2 area codes: 240, 301. Because more than one code covers the same area, 10-digit dialing is mandatory — you must dial the area code for every local call. New phone lines may be assigned any of these codes, so Frederick numbers are no longer tied to a single prefix.
History of the 301 area code
301 is one of the original area codes assigned in 1947, when AT&T and Bell Laboratories created the North American Numbering Plan and divided the country into the first 86 numbering plan areas. It has served the Frederick area ever since.
Is 301 a scam or spam risk?
301 is a legitimate geographic area code, not a premium or toll line, so a call from it costs you nothing extra. That said, scammers frequently spoof real local area codes to look familiar on caller ID. A genuine 301 number on your screen is no guarantee the caller is local or trustworthy. See spam & scam-risk area codes for how spoofing works and how to respond.
Other Maryland area codes
Explore more
See every code in Maryland, compare codes across the South region, or view all Eastern Time codes. You can also browse the 3XX block or the complete numeric list of US area codes.
New to how this all works? Start with how area codes work, then read up on overlays, 10-digit dialing, and spam & scam-risk codes. To check another number, use the area code lookup tool.
Quick answers
301 area code FAQ
Where is the 301 area code?
The 301 area code is in Maryland, serving Frederick and the surrounding area in the South region.
What time zone is 301 in?
301 is in the Eastern Time zone.
Do I have to dial 10 digits for 301?
Yes. Because Frederick is an overlay area, you must dial the full 10-digit number (area code + 7 digits) for every call.
Is 301 a toll-free or premium code?
No. 301 is a standard geographic area code, so calling it costs the same as any local or long-distance call on your plan. Toll-free calls use 800, 888, 877, 866, 855, 844 or 833.