240 area code
Where the 240 area code is, its overlay and how to dial a +1 240 number from anywhere.
The 240 area code is in Aspen Hill, Maryland, United States (Eastern (ET)). To call from abroad: +1 240 555-0123. It is an overlay, so all 10 digits are dialled.
The 240 area code is a geographic North American Numbering Plan (NANP) code covering Aspen Hill, Maryland. It has been in service since 21-Jun-1996 and sits in the Eastern (ET) time zone.
How to dial a 240 number
+1 240 555-01231 240 555-0123240 555-0123Cities in the 240 area code
A 240 number is usually in one of these places in Maryland — 6 counties.
Other Maryland area codes
Frequently asked questions
Where is the 240 area code?
The 240 area code is in Aspen Hill, Maryland, United States (Eastern (ET)).
Is 240 an overlay area code?
Yes. 240 overlays the same region as 227, 301, so callers dial all 10 digits.
Do I have to dial 10 digits for 240?
Yes — dial the area code plus the seven-digit number.
How do I call a 240 number from another country?
Dial your exit code (or +), then 1, then 240, then the number: +1 240 555-0123.
Source: NANPA numbering plan. An area code covers a region, not a precise address — a 240 number does not pinpoint a street or ZIP code.
Number holders in area code 240
Each prefix (the three digits after the area code) is assigned by NANPA to one telephone company. 800 prefixes are in use in 240, shared by 47 companies. The largest holders:
| Company | Prefixes | Share |
|---|---|---|
| Omnipoint Communications Cap Operations, LLC | 117 | 15% |
| Cellco Partnership Dba Verizon Wireless | 85 | 11% |
| New Cingular Wireless PCS, LLC | 69 | 9% |
| Paetec Itel, LLC | 63 | 8% |
| Level 3 Communications, LLC | 59 | 7% |
| Onvoy, LLC | 56 | 7% |
Source: NANPA central office code assignments. A number keeps its original prefix when it is ported to another carrier.
Complaints about 240 numbers
- Reports to the FTC, last 30 days
- 590
- Recorded messages or robocalls
- 59%
- Rank among area codes
- #142 of 670
- Most reported subjects
- Other (217)
- Reducing your debt (credit cards, mortgage, student loans) (112)
- Calls pretending to be government, businesses, or family and friends (94)
Period Aug 26 – Sep 24, 2026. These are the numbers shown on the caller ID of the reported calls; many are spoofed and do not belong to the real caller.
Source: US Federal Trade Commission, Do Not Call reported calls data (daily files).
All US area codes United States +1 Map of area code 240 — cities & rate centres