| 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 |
|---|---|---|---|
| 240-328 | Rockville | Montgomery | Landline |
| 240-776 | Port Tobacco | Charles | Landline |
| 240-418 | Laurel | Prince Georges | Wireless |
| 240-844 | Ridge | Saint Marys | Landline |
| 240-233 | Issue | Charles | Landline |
| 240-662 | Takoma Park | Montgomery | Landline |
| 240-385 | Myersville | Frederick | Landline |
| 240-643 | Silver Spring | Montgomery | Wireless |
| 240-407 | Cheltenham | Prince Georges | Landline |
| 240-988 | Laurel | Prince Georges | Wireless |
| 240-307 | Emmitsburg | Frederick | Landline |
| 240-206 | Bowie | Prince Georges | Landline |
| 240-354 | Laurel | Prince Georges | Wireless |
| 240-483 | Glen Echo | Montgomery | Landline |
| 240-544 | Bowie | Prince Georges | Landline |
| 240-258 | Ridge | Saint Marys | Landline |
| 240-345 | Ashton | Montgomery | Landline |
| 240-414 | Brentwood | Prince Georges | Landline |
| 240-624 | College Park | Prince Georges | Landline |
| 240-209 | Indian Head | Charles | Landline |