NumberResearch Membership · Data 09/21/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/21/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.

Most active assignees, all time — NPA 509
UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 29
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
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Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
— 509-364 4XXX6XXX7XXX9XXX · 3 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 GLENWOOD WA
— 509-365 1XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 LYLE WA
— 509-369 1XXX5XXX7XXX · 3 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 KLICKITAT WA
— 509-377 5XXX7XXX · 2 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 COLUMBIA WA
— 509-384 1XXX3XXX7XXX · 3 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 ROOSEVELT WA
— 509-395 1XXX5XXX7XXX9XXX · 3 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 TROUT LAKE WA
— 509-427 1XXX6XXX which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 STEVENSON WA
— 509-493 7XXX which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 WH SALMON WA
— 509-538 5XXX7XXX9XXX · 3 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 WILLARD WA
— 509-748 1XXX4XXX7XXX8XXX · 4 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 DALLESPORT WA
— 509-767 6XXX7XXX · 2 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 DALLESPORT WA
— 509-773 8XXX which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 GOLDENDALE WA
— 509-786 not yet reported which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 PROSSER WA
— 509-788 2XXX4XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 PROSSER WA
— 509-829 1XXX4XXX · 2 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 TOPPENISH WA
— 509-836 1XXX7XXX9XXX · 3 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 SUNNYSIDE WA
— 509-837 not yet reported which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 SUNNYSIDE WA
— 509-839 not yet reported which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 SUNNYSIDE WA
— 509-848 8XXX9XXX which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 HARRAH WA
— 509-854 4XXX5XXX8XXX9XXX · 2 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 GRANGER WA
— 509-865 not yet reported which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 TOPPENISH WA
— 509-874 1XXX4XXX5XXX6XXX7XXX · 3 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 WHITE SWAN WA
— 509-875 1XXX5XXX7XXX8XXX · 3 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 PATERSON WA
— 509-877 8XXX9XXX · 2 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 WAPATO WA
— 509-882 not yet reported which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 GRANDVIEW WA
— 509-894 1XXX8XXX which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 MABTON WA
— 509-896 4XXX6XXX7XXX · 3 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 MABTON WA
— 509-932 1XXX2XXX3XXX6XXX7XXX9XXX · 3 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 MATTAWA WA
— 509-973 1XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → UNITED TELEPHONE - NORTHWEST DBA CENTURYLINK - WA 4521 WHITSTRAN WA

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/21/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.