North American Numbers Source-cited · ownership disclosed
Area code
641
In service
United States · since 2000

Mason City / central-south Iowa

Serves a swath of central and southern Iowa including Marshalltown, Mason City and Ottumwa. Created in 2000 by a geographic split from 515 — the first split in Iowa since 1947.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Mason City / central-south Iowa
Type
geographic
Status
in service
In service since
2000
Projected exhaust
2037 Q1

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 641 is

Central and south-central Iowa between the Des Moines metro and the eastern codes..

Communities served wholly or partly by 641:

MarshalltownMason CityOttumwaTamaOskaloosaGrinnell

Marshalltown, Mason City and Ottumwa are the principal cities.

B · Relationships

How it relates to other codes

The codes 641 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?

Split from · 2000 515 Des Moines / central Iowa 641 split from 515 in 2000.
Related · 2000 319 Cedar Rapids / east-central Iowa Adjacent to the east.
Related · 2000 712 Sioux City / western Iowa Adjacent to the west.
What's changing. No overlay; created as a geographic split.
C · History

How 641 got here

2000-07-09
Established via geographic split from 515 — the first area-code split in Iowa since the system began in 1947.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
605
Prefixes available
195
Thousands-blocks assigned
2,180

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 641 with another code →
Sources
Wikipedia ↗
Area code 641
NumberResearch.org ↗
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).

Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.