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 |
|---|---|---|---|---|---|---|
| 2007-05-03 | 928-263 | 0–9 XXXall 10 · 5 holders which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | KINGMAN | AZ |
| — | 928-453 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | LKHAVASUCY | AZ |
| — | 928-505 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | LKHAVASUCY | AZ |
| — | 928-564 | 0XXX1XXX3XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | MEADVIEW | AZ |
| — | 928-565 | 0XXX1XXX6XXX8XXX · 4 holders which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | KINGMAN | AZ |
| — | 928-680 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | LKHAVASUCY | AZ |
| — | 928-681 | 7XXX which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | KINGMAN | AZ |
| — | 928-692 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | KINGMAN | AZ |
| — | 928-704 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | BULLHEADCY | AZ |
| — | 928-718 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | KINGMAN | AZ |
| — | 928-753 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | KINGMAN | AZ |
| — | 928-754 | 0XXX7XXX8XXX · 2 holders which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | BULLHDCYN | AZ |
| — | 928-757 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | KINGMAN | AZ |
| — | 928-758 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | BULLHEADCY | AZ |
| — | 928-763 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | BULLHEADCY | AZ |
| — | 928-764 | 0XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | CASTLEROCK | AZ |
| — | 928-765 | 0XXX1XXX3XXX4XXX5XXX6XXX8XXX · 3 holders which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | WIKIEUP | AZ |
| — | 928-766 | 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | YUCCA | AZ |
| — | 928-767 | 0XXX2XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | LKMHVRNCHS | AZ |
| — | 928-768 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | MOHAVE VLY | AZ |
| — | 928-769 | 0XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | PEACH SPG | AZ |
| — | 928-788 | 0XXX5XXX8XXX · 2 holders which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | MOHAVE VLY | AZ |
| — | 928-854 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | LKHAVASUCY | AZ |
| — | 928-855 | not yet reported which blocks → | CITIZENS UTILITIES RURAL DBA FRONTIER UT RURAL | 2172 | LKHAVASUCY | 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.