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 |
|---|---|---|---|---|---|---|
| — | 401-227 | 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | SCITUATE | RI |
| — | 401-228 | 3XXX4XXX5XXX6XXX7XXX8XXX · 2 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | PROVIDENCE | RI |
| — | 401-229 | 2XXX3XXX4XXX5XXX6XXX8XXX · 3 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | WOONSOCKET | RI |
| — | 401-234 | 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | GREENWICH | RI |
| — | 401-249 | 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 6 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | COVENTRY | RI |
| — | 401-262 | 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | W WARWICK | RI |
| — | 401-321 | 0XXX1XXX2XXX4XXX5XXX7XXX8XXX9XXX · 6 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | HOPEVALLEY | RI |
| — | 401-326 | 0XXX2XXX4XXX5XXX6XXX8XXX · 5 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | WESTERLY | RI |
| — | 401-337 | 0XXX1XXX2XXX3XXX5XXX7XXX8XXX · 5 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | WARREN | RI |
| — | 401-420 | 2XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | LTLCOMPTON | RI |
| — | 401-424 | 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BRISTOL | RI |
| — | 401-450 | 1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 2 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | PROVIDENCE | RI |
| — | 401-472 | 2XXX3XXX4XXX6XXX8XXX · 4 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | PORTSMOUTH | RI |
| — | 401-473 | 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | PROVIDENCE | RI |
| — | 401-522 | 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX · 4 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | NO KINGSTN | RI |
| — | 401-642 | 3XXX which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | PAWTUCKET | RI |
| — | 401-661 | 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | NARRAGNSTT | RI |
| — | 401-757 | 0XXX1XXX2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | CENTREDALE | RI |
| — | 401-773 | 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 5 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | WARWICK | RI |
| — | 401-793 | 0XXX1XXX6XXX which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | PROVIDENCE | RI |
| — | 401-854 | 6XXX8XXX which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | PROVIDENCE | RI |
| — | 401-856 | 4XXX5XXX6XXX8XXX · 2 holders which blocks → | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | NEWPORT | RI |
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.