NumberResearchRecent prefix assignments
1 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 |
|---|---|---|---|---|---|---|
| — | 423-926 | not yet reported which blocks → | UNITED TELEPHONE-SOUTHEAST-TN DBA CENTURYLINK - TN | 4510 | JOHNSON CY | TN |
| — | 423-928 | not yet reported which blocks → | UNITED TELEPHONE-SOUTHEAST-TN DBA CENTURYLINK - TN | 4510 | JOHNSON CY | TN |
| — | 423-929 | not yet reported which blocks → | UNITED TELEPHONE-SOUTHEAST-TN DBA CENTURYLINK - TN | 4510 | JOHNSON CY | TN |
| — | 423-942 | not yet reported which blocks → | BELLSOUTH TELECOMM INC DBA SOUTH CENTRAL BELL TEL | 9419 | JASPER | TN |
| — | 423-943 | none assigned yet which blocks → | SUNCOM DBA T-MOBILE USA | 8645 | JOHNSON CY | TN |
| — | 423-944 | not yet reported which blocks → | SCOTT COUNTY TEL. COOP., INC. | 0248 | CLINCHPORT | TN |
| — | 423-948 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → | SUNCOM DBA T-MOBILE USA | 8645 | LIMESTONE | TN |
| — | 423-949 | none assigned yet which blocks → | BLEDSOE TEL. COOP. | 0554 | DUNLAP | TN |
| — | 423-950 | not yet reported which blocks → | TN | |||
| — | 423-952 | 9XXX which blocks → | UNITED TELEPHONE-SOUTHEAST-TN DBA CENTURYLINK - TN | 4510 | JOHNSON CY | TN |
| — | 423-953 | not yet reported which blocks → | UNITED TELEPHONE-SOUTHEAST-TN DBA CENTURYLINK - TN | 4510 | JOHNSON CY | TN |
| — | 423-954 | 0XXX7XXX which blocks → | BELLSOUTH TELECOMM INC DBA SOUTH CENTRAL BELL TEL | 9419 | CHATTNOOGA | TN |
| — | 423-956 | not yet reported which blocks → | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - TN | 6673 | BRISTOL | TN |
| — | 423-957 | 2XXX3XXX4XXX5XXX7XXX8XXX · 4 holders which blocks → | SUNCOM DBA T-MOBILE USA | 8645 | HAMPTON | TN |
| — | 423-958 | not yet reported which blocks → | TN | |||
| — | 423-959 | not yet reported which blocks → | TN | |||
| — | 423-961 | 3XXX5XXX8XXX9XXX · 3 holders which blocks → | BELLSOUTH TELECOMM INC DBA SOUTH CENTRAL BELL TEL | 9419 | GEORGETOWN | TN |
| — | 423-965 | not yet reported which blocks → | HIGHLAND TEL. COOP, INC. | 0565 | DEER LODGE | TN |
| — | 423-967 | none assigned yet which blocks → | METROPCS, INC. | 5562 | KINGSPORT | TN |
| — | 423-968 | not yet reported which blocks → | UNITED TELEPHONE-SOUTHEAST-TN DBA CENTURYLINK - TN | 4510 | BRISTOL | TN |
| — | 423-972 | 1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → | SUNCOM DBA T-MOBILE USA | 8645 | GREENEVL | TN |
| — | 423-975 | not yet reported which blocks → | UNITED TELEPHONE-SOUTHEAST-TN DBA CENTURYLINK - TN | 4510 | JOHNSON CY | TN |
| — | 423-976 | not yet reported which blocks → | TN | |||
| — | 423-979 | 8XXX9XXX · 2 holders which blocks → | UNITED TELEPHONE-SOUTHEAST-TN DBA CENTURYLINK - TN | 4510 | JOHNSON CY | TN |
| — | 423-987 | not yet reported which blocks → | NEW CINGULAR WIRELESS PCS, LLC - GA | 6214 | CHATTNOOGA | TN |
| — | 423-989 | not yet reported which blocks → | UNITED TELEPHONE-SOUTHEAST-TN DBA CENTURYLINK - TN | 4510 | BRISTOL | TN |
| — | 423-990 | not yet reported which blocks → | UNITED TELEPHONE-SOUTHEAST-TN DBA CENTURYLINK - TN | 4510 | BRISTOL | TN |
| — | 423-991 | not yet reported which blocks → | NEW CINGULAR WIRELESS PCS, LLC - GA | 6214 | CHATTNOOGA | TN |
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.