| General Information about Area Code 240 | |
|---|---|
| Country | United States |
| State / Province / Territory | Maryland |
| Major City | Gaithersburg |
| Time Zone | Eastern (UTC-05:00) |
| Prefix | Primary City | County | Phone Type |
|---|---|---|---|
| 240-553 | Brentwood | Prince Georges | Landline |
| 240-241 | Bethesda | Montgomery | Landline |
| 240-395 | Chevy Chase | Montgomery | Landline |
| 240-397 | Frederick | Frederick | Wireless |
| 240-473 | Greenbelt | Prince Georges | Landline |
| 240-318 | Andrews Air Force Base | Prince Georges | Landline |
| 240-390 | Ashton | Montgomery | Landline |
| 240-684 | College Park | Prince Georges | Landline |
| 240-218 | Nanjemoy | Charles | Landline |
| 240-289 | Temple Hills | Prince Georges | Landline |
| 240-459 | Laurel | Howard | Wireless |
| 240-512 | Greenbelt | Prince Georges | Landline |
| 240-833 | Bethesda | Montgomery | Landline |
| 240-417 | District Heights | Prince Georges | Wireless |
| 240-865 | Elkridge | Howard | Landline |
| 240-269 | Brentwood | Prince Georges | Landline |
| 240-445 | Chevy Chase | Montgomery | Wireless |
| 240-368 | Waldorf | Charles | Landline |
| 240-216 | Waldorf | Charles | Wireless |
| 240-632 | Gaithersburg | Montgomery | Landline |