NumberingData
Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records

CASTILE prefixes in area code 585

NANPA records 3 assigned NXX blocks to rate center CASTILE in area code 585, 0.4% of the 676 blocks assigned in the code. A rate center is the billing geography a block is allocated to – NANPA truncates the name to ten characters, so read it as a NANPA label rather than a town. 3 holders hold those blocks, the largest being FRONTIER TELEPHONE OF ROCHESTER, INC. (1), ONVOY, LLC- NY (1), COMMIO, LLC (1). The earliest assignment on record here is 2017-03-17 and the most recent 2021-09-24. 3 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots.

3 assigned blocks – 0.4% of 585
3 holders of record
3 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
585-493 Frontier FRONTIER TELEPHONE OF ROCHESTER, INC. – yes yes
585-541 Onvoy ONVOY, LLC- NY 2017-03-17 yes yes
585-578 COMMIO, LLC 2021-09-24 yes yes

The holder is who received the block from the numbering administrator. It is not necessarily the carrier serving a given number: numbers move with their owners, and a pooled block is shared.

Who holds the blocks

HolderBrandBlocksShare here
FRONTIER TELEPHONE OF ROCHESTER, INC. Frontier 1 33.3%
ONVOY, LLC- NY Onvoy 1 33.3%
COMMIO, LLC – 1 33.3%

Frequently asked

Which prefixes belong to CASTILE in area code 585?

3 blocks: 493, 541, 578. The table above gives the holder of each.

Which carriers have numbers in CASTILE?

FRONTIER TELEPHONE OF ROCHESTER, INC. (1 block), ONVOY, LLC- NY (1 block), COMMIO, LLC (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is CASTILE a city?

It is a rate center – the unit NANPA allocates number blocks to. Its name is abbreviated to ten characters and is not necessarily a settlement: we print it as recorded rather than guess at the full name.

Other rate centers in 585

All 676 prefixes in 585