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

ST CLAIR prefixes in area code 810

NANPA records 8 assigned NXX blocks to rate center ST CLAIR in area code 810, 1.6% of the 509 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. 6 holders hold those blocks, the largest being MICHIGAN BELL TEL CO (2), LEVEL 3 COMMUNICATIONS, LLC - MI (2), NEW CINGULAR WIRELESS PCS, LLC - IL (1). The earliest assignment on record here is 2001-09-21 and the most recent 2014-09-26. 6 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 272, 507, 570, 636 – overlay codes cover the same geography, so a rate center is served by all of them.

8 assigned blocks – 1.6% of 810
6 holders of record
6 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
810-289 AT&T NEW CINGULAR WIRELESS PCS, LLC - IL 2014-09-26 yes yes
810-326 AT&T MICHIGAN BELL TEL CO – yes yes
810-328 Windstream PAETEC ITEL, LLC – yes yes
810-329 AT&T MICHIGAN BELL TEL CO – no yes
810-454 Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MI – yes yes
810-561 INTERACTIVE SERVICES NETWORK, INC. – no yes
810-637 Lumen LEVEL 3 COMMUNICATIONS, LLC - MI – yes yes
810-740 Lumen LEVEL 3 COMMUNICATIONS, LLC - MI 2001-09-21 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
MICHIGAN BELL TEL CO AT&T 2 25%
LEVEL 3 COMMUNICATIONS, LLC - MI Lumen 2 25%
NEW CINGULAR WIRELESS PCS, LLC - IL AT&T 1 12.5%
PAETEC ITEL, LLC Windstream 1 12.5%
MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MI Verizon 1 12.5%
INTERACTIVE SERVICES NETWORK, INC. – 1 12.5%

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 ST CLAIR in area code 810?

8 blocks: 289, 326, 328, 329, 454, 561, 637, 740. The table above gives the holder of each.

Which carriers have numbers in ST CLAIR?

MICHIGAN BELL TEL CO (2 blocks), LEVEL 3 COMMUNICATIONS, LLC - MI (2 blocks), NEW CINGULAR WIRELESS PCS, LLC - IL (1 block), PAETEC ITEL, LLC (1 block), MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MI (1 block), INTERACTIVE SERVICES NETWORK, INC. (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is ST CLAIR 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 810

All 509 prefixes in 810