NumberResearchThousands-blocks in 657-255
This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/19/2026
The ten 1,000-number thousand-blocks inside prefix 657-255 and who was initially assigned each. Under pooling these blocks often belong to different carriers — the single prefix-level “assignee” is usually just the pool / code holder, not who holds the numbers. ← all 657 blocks
Most active assignees, all time — NPA 657
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2015-06-02 | 657-255-0XXX | 0000–0999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC | 6010 | BUENA PARK | CA |
| 2015-06-02 | 657-255-1XXX | 1000–1999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC | 6010 | BUENA PARK | CA |
| 2019-02-27 | 657-255-2XXX | 2000–2999 | Assigned | ONVOY, LLC - CA | 649C | BUENA PARK | CA |
| 2015-04-07 | 657-255-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA | 7240 | BUENA PARK | CA |
| 2016-01-29 | 657-255-4XXX | 4000–4999 | Assigned | TWC IP ENABLED SERVICES, LLC | 793K | BUENA PARK | CA |
| 2016-02-12 | 657-255-5XXX | 5000–5999 | Assigned | ONVOY, LLC - CA | 649C | BUENA PARK | CA |
| 2016-02-12 | 657-255-6XXX | 6000–6999 | Assigned | ONVOY, LLC - CA | 649C | BUENA PARK | CA |
| 2016-01-29 | 657-255-7XXX | 7000–7999 | Assigned | ONVOY, LLC - CA | 649C | BUENA PARK | CA |
| 2016-01-29 | 657-255-8XXX | 8000–8999 | Assigned | ONVOY, LLC - CA | 649C | BUENA PARK | CA |
| 2016-03-22 | 657-255-9XXX | 9000–9999 | Assigned | PAETEC ITEL, LLC | 829J | BUENA PARK | CA |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.