NumberResearchRecent prefix assignments
0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/26/2026
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 |
|---|---|---|---|---|---|---|
| 2011-02-03 | 928-815 | 4XXX which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | WINDOWROCK | AZ |
| — | 928-283 | not yet reported which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | TUBA CITY | AZ |
| — | 928-652 | 1XXX4XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | WIDE RUINS | AZ |
| — | 928-653 | 2XXX7XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | RED VALLEY | AZ |
| — | 928-654 | 2XXX7XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | GREASEWOOD | AZ |
| — | 928-656 | none assigned yet which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | TEECNOSPOS | AZ |
| — | 928-657 | not yet reported which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | DILKON | AZ |
| — | 928-658 | 2XXX7XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | DENNEHOTSO | AZ |
| — | 928-659 | 1XXX2XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | ROCK POINT | AZ |
| — | 928-672 | 1XXX4XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | SHONTO | AZ |
| — | 928-673 | 2XXX7XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | KAIBITO | AZ |
| — | 928-674 | not yet reported which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | CHINLE | AZ |
| — | 928-677 | not yet reported which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | BLACK MESA | AZ |
| — | 928-686 | 1XXX2XXX3XXX4XXX5XXX7XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | LEUPP | AZ |
| — | 928-697 | not yet reported which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | KAYENTA | AZ |
| — | 928-698 | 5XXX6XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | LE CHEE | AZ |
| — | 928-724 | 4XXX5XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | TSAILE | AZ |
| — | 928-725 | 1XXX5XXX7XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | PINONCTNWD | AZ |
| — | 928-728 | 2XXX4XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | ROUGH ROCK | AZ |
| — | 928-729 | not yet reported which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | FTDEFIANCE | AZ |
| — | 928-736 | 3XXX4XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | TOYEI | AZ |
| — | 928-755 | 7XXX which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | GANADO | AZ |
| — | 928-781 | none assigned yet which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | CHINLE | AZ |
| — | 928-787 | 5XXX7XXX8XXX · 3 holders which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | LUKACHUKAI | AZ |
| — | 928-810 | 9XXX which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | WINDOWROCK | AZ |
| — | 928-871 | not yet reported which blocks → | NAVAJO COMM CO INC - AZ DBA FRONTIER NAVAJO COM | 4449 | WINDOWROCK | AZ |
Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/26/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.