NumberResearchRecent prefix assignments
0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026
The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.
| Assigned | NPA-NXX | Thousands-blocks taken (last-4 opening) | Code holder | OCN | Rate center | State |
|---|---|---|---|---|---|---|
| 2022-06-30 | 559-806 | 0–9 XXXall 10 · 5 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | VISALIA | CA |
| 2022-06-30 | 559-828 | 0XXX2XXX6XXX7XXX · 3 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | SELMA | CA |
| 2022-05-27 | 559-764 | 0–9 XXXall 10 · 3 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | MADERA | CA |
| 2022-05-26 | 559-218 | 0–9 XXXall 10 · 3 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | FRESNO | CA |
| 2019-04-08 | 559-605 | 0–9 XXXall 10 · 5 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | TULARE | CA |
| 2013-07-02 | 559-391 | 0–9 XXXall 10 · 5 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | REEDLEY | CA |
| 2010-03-08 | 559-537 | 0–9 XXXall 10 · 4 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | HANFORD | CA |
| 2009-05-21 | 559-517 | 0–9 XXXall 10 · 5 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | MADERA | CA |
| 2006-12-14 | 559-390 | 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | ALPAUGH | CA |
| 2005-03-09 | 559-577 | 0–9 XXXall 10 · 2 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | FRESNO | CA |
| 2004-11-02 | 559-803 | 0–9 XXXall 10 · 2 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | FRESNO | CA |
| 2001-03-22 | 559-797 | 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 7 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | CLOVIS | CA |
| — | 559-212 | 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | HANFORD | CA |
| — | 559-320 | 5XXX6XXX7XXX9XXX · 3 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | FRESNO | CA |
| — | 559-329 | 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | TULARE | CA |
| — | 559-334 | 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 6 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | VISALIA | CA |
| — | 559-339 | 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | PORTERVL | CA |
Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.