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

WASHINGTON prefixes in area code 309

NANPA records 6 assigned NXX blocks to rate center WASHINGTON in area code 309, 0.8% of the 786 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. 4 holders hold those blocks, the largest being ONVOY, LLC (2), FRONTIER NORTH, INC. - IL (2), LEVEL 3 COMMUNICATIONS, LLC - IL (1). The earliest assignment on record here is 2002-10-16 and the most recent 2026-08-26. 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 207, 252, 319, 337 – overlay codes cover the same geography, so a rate center is served by all of them.

6 assigned blocks – 0.8% of 309
4 holders of record
6 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
309-309 Onvoy ONVOY, LLC 2022-09-26 yes yes
309-444 Frontier FRONTIER NORTH, INC. - IL – yes yes
309-481 Lumen LEVEL 3 COMMUNICATIONS, LLC - IL 2002-10-16 yes yes
309-501 T-Mobile T-MOBILE USA, INC. 2003-01-02 yes yes
309-886 Frontier FRONTIER NORTH, INC. - IL – yes yes
309-951 Onvoy ONVOY, LLC 2026-08-26 yes no

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%
FRONTIER NORTH, INC. - IL Frontier 2 33.3%
LEVEL 3 COMMUNICATIONS, LLC - IL Lumen 1 16.7%
T-MOBILE USA, INC. T-Mobile 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 WASHINGTON in area code 309?

6 blocks: 309, 444, 481, 501, 886, 951. The table above gives the holder of each.

Which carriers have numbers in WASHINGTON?

ONVOY, LLC (2 blocks), FRONTIER NORTH, INC. - IL (2 blocks), LEVEL 3 COMMUNICATIONS, LLC - IL (1 block), T-MOBILE USA, 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 WASHINGTON 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 309

All 786 prefixes in 309