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

HINSDALE prefixes in area code 331

NANPA records 6 assigned NXX blocks to rate center HINSDALE in area code 331, 2.7% of the 224 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 ONVOY, LLC (2), LEVEL 3 COMMUNICATIONS, LLC - IL (1), T-MOBILE USA, INC. (1). The earliest assignment on record here is 2020-03-06 and the most recent 2024-01-05. 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 312, 406, 413, 603 – overlay codes cover the same geography, so a rate center is served by all of them.

6 assigned blocks – 2.7% of 331
5 holders of record
6 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
331-264 Lumen LEVEL 3 COMMUNICATIONS, LLC - IL 2020-03-06 yes yes
331-271 Onvoy ONVOY, LLC 2020-10-21 yes yes
331-282 Onvoy ONVOY, LLC 2021-12-10 yes yes
331-289 T-Mobile T-MOBILE USA, INC. 2022-08-12 yes yes
331-299 FRACTEL, LLC 2021-01-04 yes yes
331-317 COMMIO, LLC 2024-01-05 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
ONVOY, LLC Onvoy 2 33.3%
LEVEL 3 COMMUNICATIONS, LLC - IL Lumen 1 16.7%
T-MOBILE USA, INC. T-Mobile 1 16.7%
FRACTEL, LLC – 1 16.7%
COMMIO, LLC – 1 16.7%

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 HINSDALE in area code 331?

6 blocks: 264, 271, 282, 289, 299, 317. The table above gives the holder of each.

Which carriers have numbers in HINSDALE?

ONVOY, LLC (2 blocks), LEVEL 3 COMMUNICATIONS, LLC - IL (1 block), T-MOBILE USA, INC. (1 block), FRACTEL, LLC (1 block), COMMIO, LLC (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is HINSDALE 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 331

All 224 prefixes in 331