Maryland phone numbers and area codes
Maryland has 6 area codes and 3,731 assigned prefixes.
Look at a prefix's carrier mix below, or look up a full number on the home page.
- Mobile carrier 30%
- Local phone company 29%
- Internet / business phone carrier 37%
- Paging service 1%
- Phone company 3%
Area codes in Maryland
| Code | Area | Prefixes here |
|---|---|---|
| 227 | Western Maryland (Washington, D.C., suburbs; all counties which touch the Potomac River; Silver Spring, Hagerstown, Frederick, Rockville, Cumberland) | 142 |
| 240 | Western Maryland (Silver Spring; Washington, D.C., suburbs; all counties which touch the Potomac River; Waldorf, Hagerstown, Frederick, Rockville, Cumberland) | 785 |
| 301 | Maryland (Silver Spring; Washington, D.C., suburbs; all counties which touch the Potomac River; Waldorf, Hagerstown, Frederick, Rockville, Cumberland; and land line telephones in western Maryland) | 784 |
| 410 | Maryland (Baltimore, Annapolis, Columbia, and all counties and cities which touch the Chesapeake Bay, the Atlantic Ocean, or Delaware, except for St. Mary's County (in 301)) | 783 |
| 443 | Maryland (Baltimore, Annapolis, Columbia, and all counties and cities which touch the Chesapeake Bay, the Atlantic Ocean, or Delaware, except for St. Mary's County (in 301)) | 785 |
| 667 | Maryland (all counties and cities which touch the Chesapeake Bay, the Atlantic Ocean, or Delaware, except for St. Mary's County (in 301)) | 452 |
Biggest local calling areas
Numbers are assigned to rate centers. These have the most prefixes in Maryland (the number is how many).
Washington548Baltimore451Washington (Northern Virginia)227Towson97Laurel92Annapolis92Frederick88Gaithersburg80Catonsville70Salisbury67Pikesville64Columbia64Glen Burnie63Waldorf57Hagerstown57Ashton-Sandy Spring49Aberdeen44Bel Air37Parkville34Myersville33Elkridge33Cockeysville32Severna Park32Cumberland31Essex30Ellicottcy29Leonardtown28Westminster28Elkton28Woodlawn27Easton26Damascus23Arbutus23Severn23Fork23Prince Frederick21Edgewood21Dundalk19Odenton19Reisterstown18Argrgbsnis17Sykesville17Cambridge16Fallston16Randallstown16Oakland15Brynpklncm14Chase13Indian Head12Brandywine12Ocean City12Hughesville11Mechanicsville11La Plata11Crofton11Solomons10Sparrowspt10Chestertown10West River10Berlin9Hampstead9Centreville9Perryville9Churchville9Ridge8Mount Airy8Poolesville8North Beach8North East8Havre de Grace8Keedysville7Tompkinsville7Buckeystown7Sparksglnc7Point Deposit7Cardiff7Glenwood7New Windsor7Jarrettsville7Millersville7
Carriers in Maryland
| Carrier | Type | Prefixes | Share |
|---|---|---|---|
| Verizon (local phone) | Local phone company | 1,075 | 29% |
| T-Mobile (including Sprint) | Mobile carrier | 344 | 9% |
| Verizon Wireless | Mobile carrier | 343 | 9% |
| AT&T Mobility | Mobile carrier | 337 | 9% |
| Windstream (PAETEC) | Internet / business phone carrier | 239 | 6% |
| Onvoy | Internet / business phone carrier | 231 | 6% |
| MCImetro (Verizon Business) | Internet / business phone carrier | 204 | 5% |
| Level 3 (Lumen) | Internet / business phone carrier | 178 | 5% |
| Teleport Communications America | Internet / business phone carrier | 121 | 3% |
| Core Communications | Internet / business phone carrier | 113 | 3% |
| Bandwidth | Internet / business phone carrier | 88 | 2% |
| MetroPCS (T-Mobile) | Mobile carrier | 72 | 2% |
Most prefixes are pooled: the 10,000 numbers in each are handed out in blocks of 1,000 to different carriers, and people can also take their numbers to another carrier. So the carrier shown is where the prefix started, not a guarantee about any one number. Source: NANPA central office code records, 2026-10-10.