NumberingData
Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records

JEFFERSON prefixes in area code 920

NANPA records 7 assigned NXX blocks to rate center JEFFERSON in area code 920, 0.9% of the 785 blocks assigned in the code. A rate center is the billing geography a block is allocated to – NANPA truncates the name to ten characters, so read it as a NANPA label rather than a town. 5 holders hold those blocks, the largest being T-MOBILE USA, INC. (2), WISCONSIN BELL INC (2), TELEPORT COMMUNICATIONS AMERICA, LLC WI (1). The earliest assignment on record here is 2002-04-15 and the most recent 2002-04-15. 5 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots. The same rate center name also appears in area codes 223, 430, 440, 458 – overlay codes cover the same geography, so a rate center is served by all of them.

7 assigned blocks – 0.9% of 920
5 holders of record
5 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
920-541 AT&T TELEPORT COMMUNICATIONS AMERICA, LLC WI 2002-04-15 yes yes
920-605 T-Mobile T-MOBILE USA, INC. – yes yes
920-640 American Messaging AMERICAN MESSAGING SERVICES, LLC – no yes
920-650 AT&T NEW CINGULAR WIRELESS PCS, LLC - IL – yes yes
920-674 AT&T WISCONSIN BELL INC – no yes
920-675 AT&T WISCONSIN BELL INC – yes yes
920-747 T-Mobile T-MOBILE USA, INC. – yes yes

The holder is who received the block from the numbering administrator. It is not necessarily the carrier serving a given number: numbers move with their owners, and a pooled block is shared.

Who holds the blocks

HolderBrandBlocksShare here
T-MOBILE USA, INC. T-Mobile 2 28.6%
WISCONSIN BELL INC AT&T 2 28.6%
TELEPORT COMMUNICATIONS AMERICA, LLC WI AT&T 1 14.3%
AMERICAN MESSAGING SERVICES, LLC American Messaging 1 14.3%
NEW CINGULAR WIRELESS PCS, LLC - IL AT&T 1 14.3%

Same rate center in other codes

Overlay codes cover the same geography, so one rate center is served by all of them.

Frequently asked

Which prefixes belong to JEFFERSON in area code 920?

7 blocks: 541, 605, 640, 650, 674, 675, 747. The table above gives the holder of each.

Which carriers have numbers in JEFFERSON?

T-MOBILE USA, INC. (2 blocks), WISCONSIN BELL INC (2 blocks), TELEPORT COMMUNICATIONS AMERICA, LLC WI (1 block), AMERICAN MESSAGING SERVICES, LLC (1 block), NEW CINGULAR WIRELESS PCS, LLC - IL (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is JEFFERSON a city?

It is a rate center – the unit NANPA allocates number blocks to. Its name is abbreviated to ten characters and is not necessarily a settlement: we print it as recorded rather than guess at the full name.

Other rate centers in 920

All 785 prefixes in 920