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

ARGRGBSNIS prefixes in area code 410

NANPA records 5 assigned NXX blocks to rate center ARGRGBSNIS in area code 410, 0.6% of the 783 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. 2 holders hold those blocks, the largest being VERIZON MARYLAND, INC. (4), MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD (1). 1 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots. The same rate center name also appears in area codes 443, 667 – overlay codes cover the same geography, so a rate center is served by all of them.

5 assigned blocks – 0.6% of 410
2 holders of record
1 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
410-255 Verizon VERIZON MARYLAND, INC. – no yes
410-317 Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD – yes yes
410-360 Verizon VERIZON MARYLAND, INC. – no yes
410-437 Verizon VERIZON MARYLAND, INC. – no yes
410-439 Verizon VERIZON MARYLAND, INC. – no 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
VERIZON MARYLAND, INC. Verizon 4 80%
MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD Verizon 1 20%

Same rate center in other codes

Overlay codes cover the same geography, so one rate center is served by all of them.

Frequently asked

Which prefixes belong to ARGRGBSNIS in area code 410?

5 blocks: 255, 317, 360, 437, 439. The table above gives the holder of each.

Which carriers have numbers in ARGRGBSNIS?

VERIZON MARYLAND, INC. (4 blocks), MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MD (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is ARGRGBSNIS 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 410

All 783 prefixes in 410