NumberResearchRecent thousands-block assignments
0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/20/2026
Most carrier growth happens here, not at the prefix level: under number pooling, carriers receive individual 1,000-number blocks (e.g. 626-470-0XXX) within already-assigned prefixes. Assignments are initial assignments — the current serving carrier of individual numbers may differ due to portability.
Most active assignees, all time — NPA 831
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2022-09-21 | 831-221-4XXX | 4000–4999 | Assigned | IP HORIZON LLC | 515J | SAN ARDO | CA |
| 2022-09-21 | 831-221-7XXX | 7000–7999 | Assigned | IP HORIZON LLC | 515J | SAN ARDO | CA |
| 2022-09-21 | 831-586-3XXX | 3000–3999 | Assigned | IP HORIZON LLC | 515J | SAN JUAN | CA |
| 2022-09-21 | 831-653-4XXX | 4000–4999 | Assigned | IP HORIZON LLC | 515J | SAN LUCAS | CA |
| 2022-09-21 | 831-653-9XXX | 9000–9999 | Assigned | IP HORIZON LLC | 515J | SAN LUCAS | CA |
| 2022-09-21 | 831-731-4XXX | 4000–4999 | Assigned | IP HORIZON LLC | 515J | CASTROVL | CA |
| 2022-09-21 | 831-731-7XXX | 7000–7999 | Assigned | IP HORIZON LLC | 515J | CASTROVL | CA |
| 2022-09-21 | 831-731-9XXX | 9000–9999 | Assigned | IP HORIZON LLC | 515J | CASTROVL | CA |
| 2022-09-21 | 831-996-0XXX | 0000–0999 | Assigned | IP HORIZON LLC | 515J | TRES PINOS | CA |
| 2022-09-21 | 831-996-3XXX | 3000–3999 | Assigned | IP HORIZON LLC | 515J | TRES PINOS | CA |
| 2022-09-21 | 831-996-4XXX | 4000–4999 | Assigned | IP HORIZON LLC | 515J | TRES PINOS | CA |
| 2022-09-21 | 831-996-5XXX | 5000–5999 | Assigned | IP HORIZON LLC | 515J | TRES PINOS | CA |
| 2022-09-21 | 831-996-6XXX | 6000–6999 | Assigned | IP HORIZON LLC | 515J | TRES PINOS | CA |
| 2022-09-21 | 831-996-7XXX | 7000–7999 | Assigned | IP HORIZON LLC | 515J | TRES PINOS | CA |
| 2022-09-21 | 831-996-8XXX | 8000–8999 | Assigned | IP HORIZON LLC | 515J | TRES PINOS | CA |
| 2022-07-25 | 831-580-4XXX | 4000–4999 | Assigned | IP HORIZON LLC | 515J | GONZALES | CA |
| 2022-07-25 | 831-580-5XXX | 5000–5999 | Assigned | IP HORIZON LLC | 515J | GONZALES | CA |
| 2022-07-25 | 831-580-6XXX | 6000–6999 | Assigned | IP HORIZON LLC | 515J | GONZALES | CA |
| 2022-06-10 | 831-580-0XXX | 0000–0999 | Assigned | IP HORIZON LLC | 515J | GONZALES | CA |
| 2021-09-17 | 831-282-1XXX | 1000–1999 | Assigned | IP HORIZON LLC | 515J | MONTEREY | CA |
| 2016-08-17 | 831-268-0XXX | 0000–0999 | Assigned | IP HORIZON LLC | 515J | FELTON | CA |
| 2016-08-17 | 831-278-9XXX | 9000–9999 | Assigned | IP HORIZON LLC | 515J | BEN LOMOND | CA |
| 2016-08-17 | 831-318-9XXX | 9000–9999 | Assigned | IP HORIZON LLC | 515J | APTOS | CA |
| 2016-08-17 | 831-353-0XXX | 0000–0999 | Assigned | IP HORIZON LLC | 515J | WATSONVL | CA |
| 2016-08-17 | 831-533-0XXX | 0000–0999 | Assigned | IP HORIZON LLC | 515J | BOULDERCRK | CA |
| 2016-08-17 | 831-900-6XXX | 6000–6999 | Assigned | IP HORIZON LLC | 515J | SANTA CRUZ | CA |
| 2015-08-12 | 831-226-0XXX | 0000–0999 | Assigned | IP HORIZON LLC | 515J | SANTA CRUZ | CA |
| 2015-07-01 | 831-256-4XXX | 4000–4999 | Assigned | IP HORIZON LLC | 515J | SALINAS | 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.