667
Area code
MD
United States geographic area code, in service since 2012-03-24. Part of the 410/443/667 overlay complex — ten-digit dialing required.
Statusin service
Introduced2012-03-24
JurisdictionMD, US
Local dialing10D
Time zoneEastern
Last verified2026-09-17
Utilization 58.8% of assignable prefixes assigned
As of 09/17/2026
0%466 of ~792 assignable NXX values (200–999 excl. N11)100%
Prefix-level assignment does not equal number-level exhaustion; thousands-block pooling extends capacity. First assignment on record 2012-02-08, most recent 2026-09-16.
Area codes serve rate-center geographies, not municipal boundaries. “MD” identifies the jurisdiction, not an exact city footprint.
Top assignees
Ranked by assigned prefixes · initial assignee ≠ current carrier| Rank | Assignee | Prefixes | Share |
|---|---|---|---|
| 01 | ONVOY, LLC - MD | 84 | 18% |
| 02 | NEW CINGULAR WIRELESS PCS, LLC - DC | 58 | 12.4% |
| 03 | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 56 | 12% |
| 04 | CORE COMMUNICATIONS, INC.- MD | 41 | 8.8% |
| 05 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 24 | 5.2% |
| 06 | TON80 COMMUNICATIONS, LLC | 21 | 4.5% |
| 07 | BANDWIDTH.COM CLEC, LLC - MD | 16 | 3.4% |
| 08 | ONVOY SPECTRUM, LLC | 15 | 3.2% |
| 09 | MULTIPLE OCN LISTING | 9 | 1.9% |
| 10 | TELEPORT COMMUNICATIONS AMERICA, LLC - MD | 8 | 1.7% |
Important: these are initial assignees from NANPA CO-code records — the carrier a prefix was originally assigned to. Because of number portability, the current serving carrier of any individual number may differ.
Change history
Recorded events for this NPA- 2001-03-14 NPA 667 to Overlay NPAs 410 and 443 (Maryland)
- 2012-03-24Area code 667 entered service (created from 443).
Planning letters & orders
Primary documents| Date | Document | Subject |
|---|---|---|
| 2011-10-10 | PL-427 ↗ | NPA Code 667 to Overlay NPA Code 410/443 (Maryland) |
| 2001-03-14 | PL-266 ↗ | NPA 667 to Overlay NPAs 410 and 443 (Maryland) |