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 |
|---|---|---|---|---|---|---|
| — | 209-239 | not yet reported which blocks → | FRONTIER CALIFORNIA INC. | 4420 | MANTECA | CA |
| — | 209-364 | 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 6 holders which blocks → | FRONTIER CALIFORNIA INC. | 4420 | DOS PALOS | CA |
| — | 209-387 | 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → | FRONTIER CALIFORNIA INC. | 4420 | DOS PALOS | CA |
| — | 209-392 | 4XXX5XXX7XXX9XXX · 3 holders which blocks → | FRONTIER CALIFORNIA INC. | 4420 | DOS PALOS | CA |
| — | 209-563 | 0XXX1XXX2XXX3XXX4XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → | FRONTIER CALIFORNIA INC. | 4420 | SNELLING | CA |
| — | 209-599 | not yet reported which blocks → | FRONTIER CALIFORNIA INC. | 4420 | RIPON | CA |
| — | 209-759 | 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | FRONTIER CALIFORNIA INC. | 4420 | CLEMENTS | CA |
| — | 209-823 | not yet reported which blocks → | FRONTIER CALIFORNIA INC. | 4420 | MANTECA | CA |
| — | 209-824 | not yet reported which blocks → | FRONTIER CALIFORNIA INC. | 4420 | MANTECA | CA |
| — | 209-825 | not yet reported which blocks → | FRONTIER CALIFORNIA INC. | 4420 | MANTECA | CA |
| — | 209-858 | 8XXX which blocks → | FRONTIER CALIFORNIA INC. | 4420 | MANTECA | CA |
| — | 209-886 | 0XXX2XXX3XXX4XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → | FRONTIER CALIFORNIA INC. | 4420 | FARMINGTON | CA |
| — | 209-887 | 0XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → | FRONTIER CALIFORNIA INC. | 4420 | LINDEN | CA |
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.