240
Area code
MD
United States geographic area code, in service since 1997-06-01. Part of the 227/240/301 overlay complex — ten-digit dialing required.
Statusin service
Introduced1997-06-01
JurisdictionMD, US
Local dialing10D
Time zoneEastern
Last verified2026-09-17
Utilization 101% of assignable prefixes assigned
As of 09/17/2026
0%800 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 2001-01-09, most recent 2023-07-25.
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 | OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC | 117 | 14.6% |
| 02 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD | 85 | 10.6% |
| 03 | NEW CINGULAR WIRELESS PCS, LLC - DC | 69 | 8.6% |
| 04 | PAETEC ITEL, LLC | 63 | 7.9% |
| 05 | LEVEL 3 COMMUNICATIONS, LLC - MD | 59 | 7.4% |
| 06 | ONVOY, LLC - MD | 56 | 7% |
| 07 | VERIZON MARYLAND, INC. | 49 | 6.1% |
| 08 | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 46 | 5.8% |
| 09 | PEERLESS NETWORK OF MARYLAND, LLC | 42 | 5.3% |
| 10 | BANDWIDTH.COM CLEC, LLC - MD | 35 | 4.4% |
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- 2022-09-27 NPA 227 to Overlay NPA 240/301 (Maryland)
- 1997-06-01Area code 240 entered service (created from 301).
Planning letters & orders
Primary documents| Date | Document | Subject |
|---|---|---|
| 2022-09-27 | PL-603 ↗ | NPA 227 to Overlay NPA 240/301 (Maryland) |
| 1996-07-17 | IL-96-07-004 ↗ | Correction to 301 NPA (Maryland) Relief Plan Contact Information |
| 1996-06-21 | IL-96-06-009 ↗ | NANP-Overlay of 301 (Maryland) Numbering Plan Area (NPA) |