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 617
RCN TELECOM SERVICES, INC. - MA 19
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
— 617-209 1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 5 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 BELMONT MA
— 617-237 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 5 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 QUINCY MA
— 617-276 1XXX2XXX4XXX5XXX6XXX7XXX9XXX · 3 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 HYDE PARK MA
— 617-329 0XXX1XXX3XXX4XXX5XXX6XXX7XXX9XXX · 5 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 WINTHROP MA
— 617-334 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 6 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 SO BOSTON MA
— 617-337 2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 6 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 CHARLESTN MA
— 617-379 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX · 3 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 DORCHESTER MA
— 617-393 5XXX6XXX7XXX · 2 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 WATERTOWN MA
— 617-553 1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 JAMAICA PL MA
— 617-615 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 MILTON MA
— 617-670 8XXX which blocks → RCN TELECOM SERVICES, INC. - MA 7619 BOSTON MA
— 617-708 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 3 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 ROXBURY MA
— 617-718 3XXX4XXX5XXX · 2 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 SOMERVILLE MA
— 617-795 3XXX4XXX6XXX · 2 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 NEWTON MA
— 617-800 0XXX1XXX3XXX4XXX5XXX6XXX7XXX9XXX · 4 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 CAMBRIDGE MA
— 617-879 8XXX which blocks → RCN TELECOM SERVICES, INC. - MA 7619 BROOKLINE MA
— 617-948 5XXX which blocks → RCN TELECOM SERVICES, INC. - MA 7619 BOSTON MA
— 617-981 0XXX1XXX2XXX3XXX4XXX5XXX6XXX7XXX9XXX · 3 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 EASTBOSTON MA
— 617-987 1XXX3XXX4XXX5XXX6XXX7XXX9XXX · 5 holders which blocks → RCN TELECOM SERVICES, INC. - MA 7619 BRIGHTON MA

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.