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 |
|---|---|---|---|---|---|---|
| 2024-11-13 | 857-430 | 0–9 XXXwhole prefix which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BOSTON | MA |
| 2024-11-12 | 857-944 | 0–9 XXXwhole prefix which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BOSTON | MA |
| 2024-11-11 | 857-989 | 0–9 XXXwhole prefix which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | NEWTON | MA |
| 2020-03-23 | 857-358 | 0–9 XXXall 10 · 5 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | QUINCY | MA |
| 2016-10-25 | 857-424 | 0–9 XXXall 10 · 6 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | ROXBURY | MA |
| 2016-09-06 | 857-425 | 0–9 XXXall 10 · 7 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BRIGHTON | MA |
| 2016-08-08 | 857-419 | 0–9 XXXall 10 · 5 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | MILTON | MA |
| 2016-06-01 | 857-385 | 0–9 XXXall 10 · 3 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | DORCHESTER | MA |
| 2015-06-01 | 857-407 | 0–9 XXXall 10 · 5 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | ROXBURY | MA |
| 2011-07-12 | 857-265 | 0–9 XXXall 10 · 4 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BOSTON | MA |
| 2011-05-24 | 857-259 | 0–9 XXXall 10 · 4 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | CAMBRIDGE | MA |
| 2006-03-21 | 857-445 | 0–9 XXXall 10 · 4 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BOSTON | MA |
| 2006-03-01 | 857-272 | 0–9 XXXwhole prefix which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BOSTON | MA |
| 2001-12-17 | 857-472 | 5XXX6XXX7XXX which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BOSTON | MA |
| 2001-08-24 | 857-498 | 4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BRIGHTON | MA |
| 2001-03-29 | 857-499 | 2XXX3XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | QUINCY | MA |
| 2001-03-19 | 857-205 | not yet reported which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BOSTON | MA |
| — | 857-348 | 0–9 XXXall 10 · 4 holders which blocks → | NEW CINGULAR WIRELESS PCS, LLC - DC | 4036 | BOSTON | MA |
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.