NumberResearchThousands-blocks in 530-578
This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/21/2026
The ten 1,000-number thousand-blocks inside prefix 530-578 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 530 blocks
Most active assignees, all time — NPA 530
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| — | 530-578-0XXX | 0000–0999 | Reserved | AT&T ENTERPRISES, LLC | 516C | SOUTHTAHOE | CA |
| 2017-05-11 | 530-578-1XXX | 1000–1999 | Assigned | CENTURYLINK COMMUNICATIONS, LLC | 508J | SOUTHTAHOE | CA |
| 2017-05-11 | 530-578-2XXX | 2000–2999 | Assigned | CENTURYLINK COMMUNICATIONS, LLC | 508J | SOUTHTAHOE | CA |
| 2013-03-04 | 530-578-3XXX | 3000–3999 | Assigned | PEERLESS NETWORK OF CALIFORNIA, LLC - CA | 373F | SOUTHTAHOE | CA |
| 2013-10-30 | 530-578-4XXX | 4000–4999 | Assigned | ONVOY, LLC - CA | 649C | SOUTHTAHOE | CA |
| 2013-10-30 | 530-578-5XXX | 5000–5999 | Assigned | ONVOY, LLC - CA | 649C | SOUTHTAHOE | CA |
| 2005-05-12 | 530-578-6XXX | 6000–6999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | SOUTHTAHOE | CA |
| 2005-05-12 | 530-578-7XXX | 7000–7999 | Assigned | ONVOY, LLC - CA | 649C | SOUTHTAHOE | CA |
| 2005-05-12 | 530-578-8XXX | 8000–8999 | Assigned | ONVOY, LLC - CA | 649C | SOUTHTAHOE | CA |
| — | 530-578-9XXX | 9000–9999 | Reserved | PACIFIC BELL | 9740 | SOUTHTAHOE | CA |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/21/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.