NumberResearchThousands-blocks in 435-856
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 435-856 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
Sep 2026
Aug 2026
Jul 2026
Jun 2026
May 2026
Apr 2026
Mar 2026
Feb 2026
Jan 2026
Dec 2025
Nov 2025
Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| — | 435-856-0XXX | 0000–0999 | Reserved | LEVEL 3 COMMUNICATIONS, LLC - UT | 3231 | NEPHI | UT |
| 2009-01-23 | 435-856-1XXX | 1000–1999 | Assigned | FIRSTDIGITAL TELECOM, LLC - UT | 5727 | NEPHI | UT |
| 2023-06-02 | 435-856-2XXX | 2000–2999 | Assigned | COMCAST IP PHONE, LLC | 318J | NEPHI | UT |
| 2012-02-08 | 435-856-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | NEPHI | UT |
| 2022-04-22 | 435-856-4XXX | 4000–4999 | Assigned | CENTRAL TELCOM SVCS DBA CENTRACOM INTERACTIVE - NV | 791D | NEPHI | UT |
| 2022-04-22 | 435-856-5XXX | 5000–5999 | Assigned | CENTRAL TELCOM SVCS DBA CENTRACOM INTERACTIVE - NV | 791D | NEPHI | UT |
| 2020-10-13 | 435-856-6XXX | 6000–6999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - UT | 7530 | NEPHI | UT |
| 2017-03-01 | 435-856-7XXX | 7000–7999 | Assigned | CENTURYLINK COMMUNICATIONS, LLC | 508J | NEPHI | UT |
| — | 435-856-8XXX | 8000–8999 | Available | NEPHI | UT | ||
| 2018-08-20 | 435-856-9XXX | 9000–9999 | Assigned | PEERLESS NETWORK OF UTAH, LLC - UT | 526H | NEPHI | 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.