NumberResearchRecent thousands-block assignments
0 blocks assigned in the last 30 days · from the daily NANPA thousands-block report, 09/21/2026
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 312
New assignments by month
Sep 2026
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| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2019-08-23 | 312-668-1XXX | 1000–1999 | Assigned | LEVEL 3 TELECOM OF ILLINOIS, LLC - IL | 138G | CHICGOZN01 | IL |
| 2016-08-03 | 312-796-2XXX | 2000–2999 | Assigned | LEVEL 3 TELECOM OF ILLINOIS, LLC - IL | 138G | CHICGOZN01 | IL |
| 2015-08-10 | 312-964-4XXX | 4000–4999 | Assigned | LEVEL 3 TELECOM OF ILLINOIS, LLC - IL | 138G | CHICGOZN01 | IL |
| 2015-03-25 | 312-638-5XXX | 5000–5999 | Assigned | LEVEL 3 TELECOM OF ILLINOIS, LLC - IL | 138G | CHICGOZN01 | IL |
| 2015-02-03 | 312-966-8XXX | 8000–8999 | Assigned | LEVEL 3 TELECOM OF ILLINOIS, LLC - IL | 138G | CHICGOZN01 | IL |
| 2014-06-17 | 312-763-7XXX | 7000–7999 | Assigned | LEVEL 3 TELECOM OF ILLINOIS, LLC - IL | 138G | CHICGOZN01 | IL |
| 2014-03-10 | 312-973-5XXX | 5000–5999 | Assigned | LEVEL 3 TELECOM OF ILLINOIS, LLC - IL | 138G | CHICGOZN01 | IL |
| 2014-02-12 | 312-625-4XXX | 4000–4999 | Assigned | LEVEL 3 TELECOM OF ILLINOIS, LLC - IL | 138G | CHICGOZN01 | IL |
| 2013-02-28 | 312-754-2XXX | 2000–2999 | Assigned | LEVEL 3 TELECOM OF ILLINOIS, LLC - IL | 138G | CHICGOZN01 | IL |
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.