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

PROSSER prefixes in area code 509

NANPA records 6 assigned NXX blocks to rate center PROSSER in area code 509, 0.8% of the 763 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 UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA (2), T-MOBILE USA, INC. (1), LEVEL 3 COMMUNICATIONS, LLC - WA (1). The earliest assignment on record here is 2002-06-12 and the most recent 2002-06-12. 5 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots.

6 assigned blocks – 0.8% of 509
5 holders of record
5 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
509-303 T-Mobile T-MOBILE USA, INC. – yes yes
509-778 Lumen LEVEL 3 COMMUNICATIONS, LLC - WA 2002-06-12 yes yes
509-781 AT&T NEW CINGULAR WIRELESS PCS, LLC – yes yes
509-786 Lumen UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA – no yes
509-788 Lumen UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA – yes yes
509-832 UNITED STATES CELLULAR - WA – 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
UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA Lumen 2 33.3%
T-MOBILE USA, INC. T-Mobile 1 16.7%
LEVEL 3 COMMUNICATIONS, LLC - WA Lumen 1 16.7%
NEW CINGULAR WIRELESS PCS, LLC AT&T 1 16.7%
UNITED STATES CELLULAR - WA – 1 16.7%

Frequently asked

Which prefixes belong to PROSSER in area code 509?

6 blocks: 303, 778, 781, 786, 788, 832. The table above gives the holder of each.

Which carriers have numbers in PROSSER?

UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA (2 blocks), T-MOBILE USA, INC. (1 block), LEVEL 3 COMMUNICATIONS, LLC - WA (1 block), NEW CINGULAR WIRELESS PCS, LLC (1 block), UNITED STATES CELLULAR - WA (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is PROSSER 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 509

All 763 prefixes in 509