NumberResearchThousands-blocks in 661-673
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 661-673 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 661 blocks
Most active assignees, all time — NPA 661
New assignments by month
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| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2012-12-04 | 661-673-0XXX | 0000–0999 | Assigned | ONVOY, LLC - CA | 649C | SNCA SGCC | CA |
| — | 661-673-1XXX | 1000–1999 | Reserved | IP HORIZON LLC | 515J | SNCA SGCC | CA |
| — | 661-673-2XXX | 2000–2999 | Reserved | IP HORIZON LLC | 515J | SNCA SGCC | CA |
| 2011-10-26 | 661-673-3XXX | 3000–3999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC | 6010 | SNCA SGCC | CA |
| — | 661-673-4XXX | 4000–4999 | Reserved | IP HORIZON LLC | 515J | SNCA SGCC | CA |
| 2011-05-06 | 661-673-5XXX | 5000–5999 | Assigned | AT&T ENTERPRISES, LLC | 516C | SNCA SGCC | CA |
| 2011-10-26 | 661-673-6XXX | 6000–6999 | Assigned | NEW CINGULAR WIRELESS PCS, LLC | 6010 | SNCA SGCC | CA |
| 2011-12-15 | 661-673-7XXX | 7000–7999 | Assigned | LEVEL 3 COMMUNICATIONS, LLC - CA | 8826 | SNCA SGCC | CA |
| 2009-05-14 | 661-673-8XXX | 8000–8999 | Assigned | U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | 671J | SNCA SGCC | CA |
| 2012-12-04 | 661-673-9XXX | 9000–9999 | Assigned | ONVOY, LLC - CA | 649C | SNCA SGCC | CA |
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.