| District of Maryland area codes: 301 | |
|---|---|
| Country | United States |
| State/Province | Maryland |
| Major City | Baltimore |
| Time Zone | Eastern (UTC-05:00) |
| Prefix | County | Primary City | Company |
|---|---|---|---|
| 301-242 | Prince Georges | Brandywine, MD | Mcimetro Access Transmission Services LLC |
| 301-243 | Montgomery | Bethesda, MD | Verizon Maryland |
| 301-244 | Montgomery | Rockville, MD | Telcove Operations |
| 301-245 | Garrett | Bittinger, MD | Verizon Maryland |
| 301-246 | Charles | Nanjemoy, MD | Verizon Maryland |
| 301-247 | Saint Marys | Leonardtown, MD | New Cingular Wireless PCS - DC |
| 301-248 | Prince Georges | Fort Washington, MD | Verizon Maryland |
| 301-249 | Prince Georges | Bowie, MD | Verizon Maryland |
| 301-250 | Montgomery | Rockville, MD | Mci Worldcom Communications |
| 301-251 | Montgomery | Rockville, MD | Verizon Maryland |
| 301-252 | Montgomery | Gaithersburg, MD | Sprint Spectrum L.p. |
| 301-253 | Montgomery | Damascus, MD | Verizon Maryland |
| 301-254 | Prince Georges | Beltsville, MD | Sprint Spectrum L.p. |
| 301-255 | Montgomery | Rockville, MD | Verizon Maryland |
| 301-256 | Prince Georges | Laurel, MD | Mci Worldcom Communications |
| 301-257 | Prince Georges | Beltsville, MD | Sprint Spectrum L.p. |
| 301-258 | Montgomery | Gaithersburg, MD | Verizon Maryland |
| 301-259 | Charles | Issue, MD | Verizon Maryland |
| 301-260 | Montgomery | Ashton, MD | Verizon Maryland |
| 301-261 | Prince Georges | Glenn Dale, MD | Verizon Maryland |
There are 775 prefixes, In the code area, the major cities are Aspen Hill, MD;Bethesda, MD;Bowie, MD;Chillum, MD;. The major city is Baltimore.