Area Code 251

About Area Code 251

Area code 251 is a geographic telephone area code assigned to Mobile, Alabama. It operates in the Central time zone and was first introduced in 2001. Split from 334. Southwestern Alabama.

Within Alabama, area code 251 shares numbering capacity with 5 other area codes. The state's 5,108,468-person population (2023 Census Bureau estimate) is served by a combined 6 active codes, with 251 primarily responsible for the Mobile region. Alabama's state capital is Montgomery, and its largest city is Huntsville.

When you receive a call from a 251 number on your Caller ID, the call originated from a phone number assigned to the 251 area code — but be aware that Local Number Portability (in effect since 2003) means the caller could be physically located anywhere in the US or Canada. Area code 251 only confirms where the number was originally assigned.

Where is the 251 area code located?

Area code 251 is assigned to Mobile, Alabama, in the Central time zone. The state of Alabama uses 6 active area codes, and 251 is one of them. Calls placed from the 251 area code originate from numbers assigned by NANPA — the North American Numbering Plan Administrator — and the 251 prefix appears on Caller ID for both landline and wireless calls placed from this region.

The Central time zone observes Daylight Saving Time, shifting from UTC-6 to UTC-5 in summer. The local time shown above is always current, so you can quickly check whether it's a reasonable hour to call back.

What cities and counties use the 251 area code?

The 251 area code serves 10 notable cities, listed below in order of population. The largest city in the 251 territory is Mobile (184,892 residents in Mobile County).

• Mobile, AL — 184,892 residents (14.7% of 251 numbers)
• Huntsville, AL — 215,070 residents (17.1% of 251 numbers)
• Birmingham, AL — 196,910 residents (15.7% of 251 numbers)
• Montgomery, AL — 195,775 residents (15.6% of 251 numbers)
• Tuscaloosa, AL — 113,150 residents (9% of 251 numbers)
• Hoover, AL — 92,846 residents (7.4% of 251 numbers)
• Dothan, AL — 71,072 residents (5.7% of 251 numbers)
• Auburn, AL — 76,180 residents (6.1% of 251 numbers)
• Decatur, AL — 57,099 residents (4.5% of 251 numbers)
• Madison, AL — 54,855 residents (4.4% of 251 numbers)

Phone number format in area code 251

All phone numbers within area code 251 follow the standard North American 10-digit format:(251) NXX-XXXX. The NXX is the central office prefix (also called an "exchange") and XXXX is the subscriber line number. For long-distance calls within the NANP, dial 1 + 251 + NXX + XXXX. From outside North America, dial your country's international access code, then 1 (the NANP country code), then the 10-digit number.

If you need to verify whether a specific 251 number is wireless, landline, or VoIP, you can use our reverse phone lookup tool. Be aware that number portability means the area code no longer guarantees the caller's physical location — only where the number was first assigned.

History of area code 251

Split from 334. Southwestern Alabama.

The original 86 area codes were assigned by AT&T and Bell Labs in 1947 as part of the North American Numbering Plan. At the time, rotary-dial phones meant codes with lower digits (like 212 for NYC, 213 for LA, 312 for Chicago) were given to the largest cities because they took less time to dial. Today's area code assignments still reflect those early choices, even though touch-tone and cell phones made the original reason obsolete.

Is the 251 area code safe to answer?

Area code 251 itself is a normal geographic code with no elevated spam risk. That said, scammers can spoof any area code — including 251 — so if you don't recognize the full number, let it go to voicemail and verify the caller's identity before calling back.