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 |
|---|---|---|---|---|---|---|
| 2004-12-13 | 817-603 | 0–9 XXXwhole prefix which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | FORT WORTH | TX |
| 2004-12-13 | 817-830 | 0–9 XXXwhole prefix which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | NRICHLDHLS | TX |
| 2004-12-13 | 817-977 | 0–9 XXXwhole prefix which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | ARLINGTON | TX |
| 2002-01-10 | 817-445 | not yet reported which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | EULESS | TX |
| — | 817-200 | 3XXX4XXX6XXX7XXX8XXX · 5 holders which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | ARLINGTON | TX |
| — | 817-287 | 1XXX8XXX9XXX which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | ARLINGTON | TX |
| — | 817-288 | none assigned yet which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | FORT WORTH | TX |
| — | 817-342 | not yet reported which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | ARLINGTON | TX |
| — | 817-509 | none assigned yet which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | FORT WORTH | TX |
| — | 817-574 | 3XXX which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | EULESS | TX |
| — | 817-575 | 7XXX9XXX which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | ARLINGTON | TX |
| — | 817-639 | not yet reported which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | FORT WORTH | TX |
| — | 817-708 | 2XXX which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | FORT WORTH | TX |
| — | 817-712 | not yet reported which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | NRICHLDHLS | TX |
| — | 817-869 | not yet reported which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | FORT WORTH | TX |
| — | 817-872 | not yet reported which blocks → | LEVEL 3 OF TELECOM OF TEXAS, LLC - TX | 7516 | FORT WORTH | TX |
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.