NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

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.

Most active assignees, all time — NPA 559
LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 26
New assignments by month Sep 2026 Aug 2026 Jul 2026 Jun 2026 May 2026 Apr 2026 Mar 2026 Feb 2026 Jan 2026 Dec 2025 Nov 2025 Oct 2025
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Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
2005-09-06 559-892 0–9 XXXall 10 · 4 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 FRESNO CA
2002-06-14 559-316 0–9 XXXall 10 · 7 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 FOWLER CA
— 559-256 not yet reported which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 FRESNO CA
— 559-295 2XXX3XXX4XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 COALINGA CA
— 559-296 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 FIREBAUGH CA
— 559-302 0XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 VISALIA CA
— 559-326 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 CLOVIS CA
— 559-342 0XXX1XXX2XXX5XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 PIXLEY CA
— 559-382 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 MENDOTA CA
— 559-482 2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 BURREL CA
— 559-484 0XXX2XXX5XXX6XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 TIPTON CA
— 559-543 0XXX2XXX3XXX4XXX5XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 HURON CA
— 559-631 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 TULARE CA
— 559-632 0XXX1XXX2XXX3XXX5XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 RIVERDALE CA
— 559-633 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 8 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 LEMOORE CA
— 559-634 0XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 KINGSBURG CA
— 559-639 0XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 HANFORD CA
— 559-640 0XXX2XXX7XXX9XXX · 3 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 THREERIVRS CA
— 559-644 0XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 CARUTHERS CA
— 559-648 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 DINUBA CA
— 559-654 0XXX2XXX5XXX · 3 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 SEQUOIA CA
— 559-718 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 MADERA CA
— 559-769 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 WOODLAKE CA
— 559-819 0XXX1XXX3XXX4XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 SELMA CA
— 559-847 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 PARLIER CA
— 559-927 0XXX3XXX4XXX5XXX6XXX7XXX · 4 holders which blocks → LEVEL 3 TELECOM OF CALIFORNIA, LP - CA 7718 STRATFORD 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.