NumberResearchThousands-blocks in 435-558
This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/20/2026
The ten 1,000-number thousand-blocks inside prefix 435-558 and who was initially assigned each. Under pooling these blocks often belong to different carriers — the single prefix-level “assignee” is usually just the pool / code holder, not who holds the numbers. ← all 435 blocks
Most active assignees, all time — NPA 435
New assignments by month
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| — | 435-558-0XXX | 0000–0999 | Reserved | NEW CINGULAR WIRELESS PCS, LLC | 6010 | RICHFIELD | UT |
| 2012-11-21 | 435-558-1XXX | 1000–1999 | Assigned | ONVOY, LLC - UT | 871E | RICHFIELD | UT |
| 2015-09-24 | 435-558-2XXX | 2000–2999 | Assigned | FIRSTDIGITAL COMMUNICATIONS, LLC | 716D | RICHFIELD | UT |
| 2016-02-12 | 435-558-3XXX | 3000–3999 | Assigned | ONVOY, LLC - UT | 871E | RICHFIELD | UT |
| 2018-02-14 | 435-558-4XXX | 4000–4999 | Assigned | PEERLESS NETWORK OF UTAH, LLC - UT | 526H | RICHFIELD | UT |
| 2012-08-08 | 435-558-5XXX | 5000–5999 | Assigned | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - UT | 6571 | RICHFIELD | UT |
| 2013-08-20 | 435-558-6XXX | 6000–6999 | Assigned | ONVOY, LLC - UT | 871E | RICHFIELD | UT |
| 2017-03-01 | 435-558-7XXX | 7000–7999 | Assigned | CENTURYLINK COMMUNICATIONS, LLC | 508J | RICHFIELD | UT |
| 2018-09-25 | 435-558-8XXX | 8000–8999 | Assigned | ONVOY, LLC - UT | 871E | RICHFIELD | UT |
| 2020-12-29 | 435-558-9XXX | 9000–9999 | Assigned | TERRA NOVA TELECOM INC. | 145J | RICHFIELD | UT |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.