Frontier phone number blocks and OCNs in the US

The legal entities NANPA lists

Every holder in NANPA’s table that the brand map groups under Frontier, by the numbers allocated to it and with its operating company number (OCN), the code the table identifies a carrier by. Names are printed as the regulator writes them. Holdings are counted in numbers, not table rows, because rows differ in size: a central office code (NPA-NXX) is 10,000 numbers and a thousands-block 1,000. A pooled code counts for its code holder only where no thousands-block row of the table covers it, so no number is counted twice.

How a lookup reads these numbers

The North American plan leaves a number’s line type to the holder of its block, so a lookup reads it from the holder: 0.0% of Frontier’s numbers read as VoIP, 0.0% as mobile, and for 100.0% the holder settles neither, so the line type stays fixed_line_or_mobile.

The reading is Spaw’s classification of each holder: the holder’s regulatory filing (in the US its FCC Form 499 filing type) and its own description, matched on the name the regulator’s table gives it. It is a lower bound, not a measurement of the numbers, and it says what a lookup answers, not what Frontier is.

The area codes with most of its numbers

Frontier’s entities hold numbers under 132 area codes. The share is its part of the numbers NANPA lists as allocated under each code.

Thousands-blocks in pooled codes

In a pooled US code NANPA assigns the code’s ten thousands-blocks one by one, often to carriers other than the code holder, and a lookup names the holder of the number’s own thousands-block where NANPA lists one. Frontier’s entities hold 18,164 thousands-blocks: 17,845 inside codes its own entities hold, 281 inside codes of other brands and 38 inside codes of holders the brand map does not group, which this page counts but does not name.

Other holders hold 16,652 thousands-blocks inside Frontier’s codes, 2,036 of them holders the brand map does not group. The largest: Inteliquent 4,369, Lumen 1,968, Verizon 1,643, AT&T 1,539, T-Mobile 1,332, Bandwidth 1,226.

Assignments by year

The codes and thousands-blocks the table still lists under Frontier’s entities, by the year NANPA dates their assignment. A block returned since is no longer in the table, so earlier years read low; 4.2% of the rows carry a date. NANPA dates nothing before 2001 and no retained block.

What this page cannot say

• A regulator’s table records the original allocation of each block, never who serves a number today: a number ported away from Frontier keeps its block, and a lookup still names the block’s holder for it.
• The carrier a lookup names is not the caller, the app or the subscriber. Caller ID can be spoofed, so the holder of a calling number’s block may not have carried the call at all.
• Spaw does no reverse lookup and names no subscriber: nothing here says who owns or uses any number.
• Shares are shares of the regulator’s own table, not of subscribers, lines in service or traffic.
• In a pooled US code a lookup names the holder of the number’s own thousands-block where NANPA lists one, otherwise the code holder; Canada’s table is code-level.
• The grouping under Frontier is Spaw’s carrier brand map of 2026-09-24: legal entities, subsidiaries and former names under the brand the network trades as today. Networks change hands, and the map is reviewed at least yearly.

Frontier and the other brand names on this page are trademarks of their owners, used only to name the networks the regulators’ tables list. Spaw is not affiliated with any of them.

Other carriers in the United States

• AT&T
• Verizon
• T-Mobile
• Inteliquent
• Lumen
• Bandwidth
• Windstream
• Comcast
• Peerless Network
• Spok
• Brightspeed
• Charter
• Telnyx
• Commio
• Consolidated Communications
• Optimum
• TPx
• Ziply Fiber
• Boost Mobile
• altafiber
• Hawaiian Telcom
• Mediacom
• GCI
• Every carrier, by the numbers it holds
• Phone numbers in the United States
• NANPA numbering reports
• Look up a number

NANPA numbering reports file dated 2026-09-27 · carrier brand map 2026-09-24 · page changed 2026-09-27