The 641 area code covers Mason City, Marshalltown and 204 more places in Iowa.
Area code 641 is in Iowa, on Central Time. In the 641 area, phone numbers are given out most in Cerro Gordo County, then Marshall and Marion counties. It has been in service since July 9, 2000.
- Where
- 8 counties in Iowa, mostly Cerro Gordo County, Marshall County and Marion County
- Time zone
- Central Time
- In service since
- July 9, 2000
- Shares its area with
- No other area code
- Prefixes in use
- 584
- How to dial
- Local calls inside 641 can still be dialed with just 7 digits.
Find out who called you from a 641 number.
Enter the full 10-digit number to see who it is listed to and the city and state on the listing. It is the same free check as our who called me lookup. To see only the caller ID name on the number, use our free CNAM lookup. To see whether it is a mobile, a landline or a VoIP line, use our free VoIP checker. To see which carrier a (641) number is on today, use our free carrier lookup.
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Mason City holds 3% of the phone prefixes in area code 641.
A prefix is the three digits after the area code, and NANPA assigns each one to a town. Counting the 584 prefixes in use shows where 641 numbers are actually given out.
- Mason City20 prefixes, 3%
- Marshalltown16 prefixes, 3%
- Ottumwa15 prefixes, 3%
- Pella12 prefixes, 2%
- Oskaloosa12 prefixes, 2%
- New Hampton12 prefixes, 2%
- Charles City11 prefixes, 2%
- Newton10 prefixes, 2%
Also served: Fairfield, Grinnell, Knoxville and Little Cedar and 194 smaller places.
Windstream holds the most phone number prefixes in area code 641: 123 of 584.
NANPA, which runs the North American numbering plan, assigns each prefix (the three digits after the area code) to one carrier. Here is how the 584 prefixes in use in 641 divide between carriers; holders this page does not name are grouped as other carriers.
| Carrier | Prefixes | Share |
|---|---|---|
| WindstreamLandline company | 123 | 21% |
| UScellularMobile network | 39 | 7% |
| Qwest (Lumen)Lumen's landline company | 30 | 5% |
| AT&T MobilityMobile network | 28 | 5% |
| Farmers Telephone | 28 | 5% |
| T-MobileMobile network | 23 | 4% |
| 61 other carriers | 313 | 54% |
72% of these prefixes are pooled, which means the blocks of 1,000 numbers inside them can belong to other carriers. Any number can also have been moved to another carrier since, so this shows who holds the prefixes, not who serves a given number.
Want the carrier of one exact number? Our free carrier lookup checks it, because numbers move between carriers.
Source: NANPA central office code assignments, October 1, 2026.
641 has covered the same ground since 2000.
2000
641 starts on July 9, 2000, split off from 515.
A 641 number on your screen can still be a scam, because caller ID is easy to fake.
- Let an unknown call go to voicemail. A real caller leaves a message; a robocaller usually does not.
- Look the number up with the box above before you call back, because calling back tells a robocaller your line is live.
- Hang up on anyone who wants gift cards, crypto or a wire transfer, or asks you to read out a code that was just texted to you.
- Report unwanted robocalls at reportfraud.ftc.gov, or paste a suspicious message into our free scam checker.
The area codes closest to 641 are 515, 319 and 563.
This list measures the distance between the centres of each area, across state lines, and shows codes that share one area together.
Iowa has 4 other area codes.
These are the questions people ask most about area code 641.
Where is area code 641?
641 covers Mason City, Marshalltown, Ottumwa and Pella and 202 more places in Iowa. In the 641 area, phone numbers are given out most in Cerro Gordo County, then Marshall and Marion counties.
What state is area code 641 in?
Iowa. 641 is an Iowa area code on Central Time.
What cities use area code 641?
The places holding the most 641 prefixes are Mason City, Marshalltown, Ottumwa, Pella, Oskaloosa, New Hampton, Charles City and Newton, out of 206 places in all. The count comes from NANPA's prefix assignments as of October 1, 2026.
Which phone company owns area code 641?
No single phone company owns 641. NANPA's records show Windstream holds the most 641 prefixes, 123 of 584, followed by UScellular and Qwest (Lumen). Numbers move between carriers, so check one exact number with a carrier lookup.
What time zone is area code 641 in?
641 is on Central Time.
When did area code 641 start?
641 went into service on July 9, 2000, when it was split off from 515.
How do I dial a 641 number?
Local calls inside 641 can still be dialed with just 7 digits.
Is 641 a toll-free number?
No. 641 is a regular area code for Mason City and Marshalltown in Iowa, not a toll-free one. The toll-free codes in North America are 800, 833, 844, 855, 866, 877 and 888.
What area codes are near 641?
The closest are 515 (Des Moines, Iowa), 319 (Cedar Rapids, Iowa), 563 (Davenport, Iowa) and 712 (Sioux City, Iowa), measured between the centres of each area.
Who called me from a 641 number?
Enter the full 10-digit number in the lookup above. It returns the listed owner where there is a public record, where the number is registered, and whether it is a mobile, a landline or a VoIP line.
Is area code 641 a scam?
641 is a real Iowa area code, so the code itself is not a warning sign. Scam callers fake local-looking numbers on purpose, so judge the call by what the caller asks for, and look the number up before calling back.
Put this lookup on your site: our free area code widget takes two lines of code and shows any US area code's state, time zone and local time.
Source: NANPA, the North American Numbering Plan Administrator: its area code database and prefix assignments, as of October 1, 2026.