| Prefixes | City | County | Line Type | Company |
|---|---|---|---|---|
| 240-205 | Rockville | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-206 | Bowie | Prince Georges | Landline | Xo Maryland, Llc |
| 240-207 | Damascus | Montgomery | Landline | Cavalier East Llc Md |
| 240-209 | Columbia | Howard | Landline | Global Naps South, Inc. Md |
| 240-210 | Waldorf | Charles | Cell Phone | New Cingular Wireless Pcs,... |
| 240-214 | Gettysburg | Adams | Landline | Global Naps South, Inc. Md |
| 240-215 | Frederick | Frederick | Landline | Telcove Operations, Inc. Md |
| 240-216 | Waldorf | Charles | Cell Phone | Nextel Communications, Inc. |
| 240-217 | Hagerstown | Washington | Cell Phone | Omnipoint Communications Ca... |
| 240-221 | Rockville | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-222 | Waldorf | Charles | Landline | Cavalier Telephone Midatla... |
| 240-223 | Bethesda | Montgomery | Landline | Allegiance Telecom, Inc. Md |
| 240-228 | Laurel | Howard | Landline | Verizon Maryland, Inc. |
| 240-229 | Waldorf | Charles | Landline | Broadwing Communications. L... |
| 240-230 | La Plata | Charles | Landline | Global Crossing Local Servi... |
| 240-232 | Bowie | Prince Georges | Landline | Broadwing Communications. L... |
| 240-233 | Newburg | Charles | Landline | Teleport Communications Gro... |
| 240-235 | Chevy Chase | Montgomery | Landline | Paetec Communications, Inc.... |
| 240-236 | Frederick | Frederick | Landline | Verizon Maryland, Inc. |
| 240-237 | Lexington Park | Saint Marys | Landline | Teleport Communications Gro... |
| 240-238 | Rockville | Montgomery | Landline | Paetec Communications, Inc.... |
| 240-241 | Beltsville | Prince Georges | Landline | Starpower Communications, L... |
| 240-242 | Silver Spring | Montgomery | Landline | Starpower Communications, L... |
| 240-243 | Gaithersburg | Montgomery | Landline | Allegiance Telecom, Inc. Md |
| 240-244 | Clinton | Prince Georges | Landline | Starpower Communications, L... |
| 240-245 | Bowie | Prince Georges | Landline | Starpower Communications, L... |
| 240-246 | Gaithersburg | Montgomery | Landline | Starpower Communications, L... |
| 240-247 | Silver Spring | Montgomery | Landline | Allegiance Telecom, Inc. Md |
| 240-248 | Washington | District Of Columbia | Landline | Global Naps South, Inc. Md |
| 240-249 | Mechanicsville | Saint Marys | Landline | Teleport Communications Gro... |
| 240-250 | Gaithersburg | Montgomery | Landline | Global Naps South, Inc. Md |
| 240-252 | Germantown | Montgomery | Landline | Level 3 Communications, Llc... |
| 240-253 | Oxon Hill | Prince Georges | Landline | Global Crossing Local Servi... |
| 240-254 | Hughesville | Charles | Landline | Teleport Communications Gro... |
| 240-256 | Fairfax | Fairfax | Landline | Teleport Communications Gro... |
| 240-258 | Saint Inigoes | Saint Marys | Landline | Teleport Communications Gro... |
| 240-260 | Hyattsville | Prince Georges | Landline | Allegiance Telecom, Inc. Md |
| 240-263 | Upper Marlboro | Prince Georges | Landline | Tidalwave Telephone Inc. |
| 240-264 | Laurel | Prince Georges | Landline | Verizon Maryland, Inc. |
| 240-265 | Laurel | Prince Georges | Landline | Tidalwave Telephone Inc. |
| 240-268 | Rockville | Montgomery | Landline | Allegiance Telecom, Inc. Md |
| 240-271 | Silver Spring | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-273 | Fort Washington | Prince Georges | Landline | Broadwing Communications. L... |
| 240-274 | Oxon Hill | Prince Georges | Cell Phone | New Cingular Wireless Pcs,... |
| 240-276 | Rockville | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-277 | Silver Spring | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-280 | Laurel | Prince Georges | Landline | Comcast Phone Of Northern M... |
| 240-281 | Hyattsville | Prince Georges | Cell Phone | New Cingular Wireless Pcs,... |
| 240-282 | Middletown | Frederick | Landline | Global Naps South, Inc. Md |
| 240-283 | Rockville | Montgomery | Landline | Paetec Communications, Inc.... |
| 240-284 | Frostburg | Allegany | Landline | Nationsline, Inc. Md |
| 240-285 | Frederick | Frederick | Cell Phone | Cellco Partnership Dba Veri... |
| 240-286 | Washington | District Of Columbia | Cell Phone | Nextel Communications, Inc. |
| 240-288 | Thurmont | Frederick | Landline | Nationsline, Inc. Md |
| 240-289 | Oxon Hill | Prince Georges | Landline | Cavalier Telephone Midatla... |
| 240-290 | Rockville | Montgomery | Landline | Allegiance Telecom, Inc. Md |
| 240-291 | Hagerstown | Washington | Cell Phone | New Cingular Wireless Pcs,... |
| 240-292 | Silver Spring | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-293 | Silver Spring | Montgomery | Landline | Starpower Communications, L... |
| 240-294 | Laurel | Prince Georges | Landline | Xo Maryland, Llc |
| 240-295 | Laurel | Prince Georges | Landline | Cavalier Telephone Midatla... |
| 240-296 | Hyattsville | Prince Georges | Landline | Cavalier Telephone Midatla... |
| 240-297 | Greenbelt | Prince Georges | Landline | Level 3 Communications, Llc... |
| 240-298 | Hollywood | Saint Marys | Cell Phone | Cellco Partnership Dba Veri... |
| 240-299 | Waldorf | Charles | Cell Phone | Nextel Communications, Inc. |
| 240-303 | Clinton | Prince Georges | Landline | Cavalier Telephone Midatla... |
| 240-304 | District Heights | Prince Georges | Cell Phone | Nextel Communications, Inc. |
| 240-305 | Silver Spring | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-306 | Rockville | Montgomery | Landline | Allegiance Telecom, Inc. Md |
| 240-307 | Emmitsburg | Frederick | Landline | At&t Local |
| 240-308 | Washington | District Of Columbia | Cell Phone | New Cingular Wireless Pcs,... |
| 240-310 | Hagerstown | Washington | Landline | Uscoc Of Cumberland, Inc. D... |
| 240-312 | Capitol Heights | Prince Georges | Landline | Cavalier Telephone Midatla... |
| 240-313 | Hagerstown | Washington | Landline | Verizon Maryland, Inc. |
| 240-314 | Rockville | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-315 | Frederick | Frederick | Landline | Verizon Maryland, Inc. |
| 240-317 | Lexington Park | Saint Marys | Landline | Starpower Communications, L... |
| 240-318 | Clinton | Prince Georges | Landline | Verizon Maryland, Inc. |
| 240-320 | Washington | District Of Columbia | Landline | Cavalier East Llc Md |
| 240-321 | Swanton | Garrett | Landline | Uscoc Of Cumberland, Inc. D... |
| 240-326 | Upper Marlboro | Prince Georges | Landline | Cavalier Telephone Midatla... |
| 240-328 | Rockville | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-329 | Hagerstown | Washington | Landline | Level 3 Communications, Llc... |
| 240-330 | Germantown | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-332 | Silver Spring | Montgomery | Landline | Global Naps South, Inc. Md |
| 240-333 | Bethesda | Montgomery | Landline | Cavalier East Llc Md |
| 240-334 | Bowie | Prince Georges | Landline | Global Crossing Local Servi... |
| 240-335 | Lanham | Prince Georges | Landline | Cavalier Telephone Midatla... |
| 240-337 | Newport Beach | Orange | Landline | Global Naps South, Inc. Md |
| 240-338 | Bowie | Prince Georges | Cell Phone | Cellco Partnership Dba Veri... |
| 240-339 | Upper Marlboro | Prince Georges | Landline | Cavalier East Llc Md |
| 240-342 | Olney | Montgomery | Landline | Starpower Communications, L... |
| 240-344 | Frederick | Frederick | Cell Phone | New Cingular Wireless Pcs,... |
| 240-345 | Highland | Howard | Landline | Level 3 Communications, Llc... |
| 240-346 | Waldorf | Charles | Cell Phone | Sprint Spectrum L.p. |
| 240-348 | Clinton | Prince Georges | Landline | Level 3 Communications, Llc... |
| 240-349 | La Plata | Charles | Landline | Global Crossing Local Servi... |
| 240-350 | Bowie | Prince Georges | Cell Phone | Sprint Spectrum L.p. |
| 240-351 | Silver Spring | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-353 | Silver Spring | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-354 | Upper Marlboro | Prince Georges | Cell Phone | Sprint Spectrum L.p. |
| 240-355 | Gaithersburg | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-356 | Myersville | Frederick | Landline | Level 3 Communications, Llc... |
| 240-359 | Gaithersburg | Montgomery | Landline | Global Naps South, Inc. Md |
| 240-361 | Gaithersburg | Montgomery | Landline | Cavalier Telephone Midatla... |
| 240-362 | Cumberland | Allegany | Landline | Verizon Maryland, Inc. |
| 240-364 | Gaithersburg | Montgomery | Landline | Cavalier East Llc Md |
| 240-366 | Williamsport | Washington | Landline | At&t Local |
| 240-367 | Frederick | Frederick | Cell Phone | Nextel Communications, Inc. |
| 240-368 | Darien | Fairfield | Landline | Global Naps South, Inc. Md |
| 240-370 | Washington | District Of Columbia | Cell Phone | Sprint Spectrum L.p. |
| 240-371 | Laurel | Prince Georges | Landline | Global Naps South, Inc. Md |
| 240-372 | Gaithersburg | Montgomery | Cell Phone | Nextel Communications, Inc. |
| 240-373 | Fort George G Meade | Anne Arundel | Landline | Verizon Maryland, Inc. |
| 240-374 | Laurel | Prince Georges | Landline | Global Crossing Local Servi... |
| 240-375 | Hyattsville | Prince Georges | Cell Phone | Nextel Communications, Inc. |
| 240-377 | Indian Head | Charles | Landline | Global Crossing Local Servi... |
| 240-379 | Frederick | Frederick | Landline | Verizon Maryland, Inc. |
| 240-380 | Bethesda | Montgomery | Cell Phone | Cellco Partnership Dba Veri... |
| 240-381 | Fort Washington | Prince Georges | Cell Phone | New Cingular Wireless Pcs,... |
| 240-383 | Bethesda | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-384 | Hollywood | Saint Marys | Landline | Global Naps South, Inc. Md |
| 240-386 | Gaithersburg | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-387 | Beltsville | Prince Georges | Landline | Cavalier East Llc Md |
| 240-388 | Gaithersburg | Montgomery | Cell Phone | Nextel Communications, Inc. |
| 240-389 | Olney | Montgomery | Landline | Atx Telecommunications Serv... |
| 240-390 | Columbia | Howard | Landline | Cavalier Telephone Midatla... |
| 240-391 | Greenbelt | Prince Georges | Landline | Global Crossing Local Servi... |
| 240-392 | Suitland | Prince Georges | Landline | Starpower Communications, L... |
| 240-393 | Silver Spring | Montgomery | Cell Phone | Cellco Partnership Dba Veri... |
| 240-394 | Mount Airy | Frederick | Cell Phone | New Cingular Wireless Pcs,... |
| 240-395 | Bethesda | Montgomery | Landline | Cavalier Telephone Midatla... |
| 240-396 | Bethesda | Montgomery | Landline | Global Crossing Local Servi... |
| 240-398 | Hyattsville | Prince Georges | Cell Phone | Nextel Communications, Inc. |
| 240-399 | Rockville | Montgomery | Landline | Xo Maryland, Llc |
| 240-401 | Gaithersburg | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-403 | Rockville | Montgomery | Landline | Cavalier Telephone Midatla... |
| 240-404 | Germantown | Montgomery | Landline | Xo Maryland, Llc |
| 240-405 | Frederick | Frederick | Landline | Us Lec Of Maryland, Inc. |
| 240-407 | Temple Hills | Prince Georges | Landline | Global Crossing Local Servi... |
| 240-409 | Frederick | Frederick | Cell Phone | New Cingular Wireless Pcs,... |
| 240-412 | Waldorf | Charles | Cell Phone | Sprint Spectrum L.p. |
| 240-413 | Washington | District Of Columbia | Cell Phone | Omnipoint Communications Ca... |
| 240-416 | Waldorf | Charles | Cell Phone | New Cingular Wireless Pcs,... |
| 240-417 | Silver Spring | Montgomery | Cell Phone | Nextel Communications, Inc. |
| 240-418 | Rockville | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-419 | Waldorf | Charles | Cell Phone | Cellco Partnership Dba Veri... |
| 240-420 | Hagerstown | Washington | Landline | Verizon Maryland, Inc. |
| 240-421 | Silver Spring | Montgomery | Cell Phone | Omnipoint Communications Ca... |
| 240-422 | Frederick | Frederick | Cell Phone | Omnipoint Communications Ca... |
| 240-423 | Rockville | Montgomery | Cell Phone | Omnipoint Communications Ca... |
| 240-424 | Washington | District Of Columbia | Cell Phone | Sprint Spectrum L.p. |
| 240-425 | Rockville | Montgomery | Landline | Dslnet Communications Va, I... |
| 240-426 | Silver Spring | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-427 | Waldorf | Charles | Landline | Xo Maryland, Llc |
| 240-429 | Upper Marlboro | Prince Georges | Cell Phone | Cellco Partnership Dba Veri... |
| 240-430 | Silver Spring | Montgomery | Landline | Cavalier Telephone Midatla... |
| 240-431 | Westminster | Orange | Cell Phone | Sprint Spectrum L.p. |
| 240-432 | Silver Spring | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-433 | Silver Spring | Montgomery | Landline | Cavalier Telephone Midatla... |
| 240-434 | California | Saint Marys | Landline | Broadwing Communications. L... |
| 240-436 | Frederick | Frederick | Landline | Telcove Operations, Inc. Md |
| 240-441 | Bowie | Prince Georges | Cell Phone | Omnipoint Communications Ca... |
| 240-442 | Oakland | Garrett | Landline | Verizon Maryland, Inc. |
| 240-446 | Frederick | Frederick | Cell Phone | Cellco Partnership Dba Veri... |
| 240-447 | Rockville | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-449 | Gaithersburg | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-450 | Silver Spring | Montgomery | Landline | Cavalier Telephone Midatla... |
| 240-453 | Rockville | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-454 | Gaithersburg | Montgomery | Landline | Paetec Communications, Inc.... |
| 240-455 | Suitland | Prince Georges | Landline | Paetec Communications, Inc.... |
| 240-456 | Laurel | Prince Georges | Landline | Verizon Maryland, Inc. |
| 240-460 | Bowie | Prince Georges | Cell Phone | New Cingular Wireless Pcs,... |
| 240-461 | Silver Spring | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-462 | Silver Spring | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-463 | Upper Marlboro | Prince Georges | Cell Phone | New Cingular Wireless Pcs,... |
| 240-464 | Gaithersburg | Montgomery | Cell Phone | Nextel Communications, Inc. |
| 240-465 | Clarks Summit | Lackawanna | Landline | Global Naps South, Inc. Md |
| 240-468 | Fort Washington | Prince Georges | Cell Phone | Sprint Spectrum L.p. |
| 240-469 | Hagerstown | Washington | Cell Phone | Sprint Spectrum L.p. Md |
| 240-471 | Silver Spring | Montgomery | Landline | Global Crossing Local Servi... |
| 240-472 | Bowie | Prince Georges | Cell Phone | New Cingular Wireless Pcs,... |
| 240-473 | College Park | Prince Georges | Landline | Cavalier Telephone Midatla... |
| 240-475 | Silver Spring | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-476 | Silver Spring | Montgomery | Cell Phone | Omnipoint Communications Ca... |
| 240-477 | Gaithersburg | Montgomery | Landline | Lightwave Communications, L... |
| 240-478 | Washington | District Of Columbia | Cell Phone | New Cingular Wireless Pcs,... |
| 240-481 | Gaithersburg | Montgomery | Cell Phone | Omnipoint Communications Ca... |
| 240-482 | Bethesda | Montgomery | Landline | Us Lec Of Maryland, Inc. |
| 240-483 | Columbia | Howard | Landline | Comcast Phone Of Northern M... |
| 240-485 | Silver Spring | Montgomery | Landline | Us Lec Of Maryland, Inc. |
| 240-486 | Kensington | Montgomery | Cell Phone | Omnipoint Communications Ca... |
| 240-487 | Hyattsville | Prince Georges | Landline | Us Lec Of Maryland, Inc. |
| 240-489 | Poolesville | Montgomery | Landline | Xo Maryland, Llc |
| 240-490 | Frederick | Frederick | Cell Phone | Omnipoint Communications Ca... |
| 240-491 | Silver Spring | Montgomery | Landline | Global Crossing Local Servi... |
| 240-492 | Upper Marlboro | Prince Georges | Landline | Us Lec Of Maryland, Inc. |
| 240-493 | Oxon Hill | Prince Georges | Landline | Us Lec Of Maryland, Inc. |
| 240-494 | Silver Spring | Montgomery | Landline | Cavalier East Llc Md |
| 240-497 | Bethesda | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-498 | Rockville | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-499 | Rockville | Montgomery | Landline | Us Lec Of Maryland, Inc. |
| 240-501 | Hyattsville | Prince Georges | Cell Phone | Sprint Spectrum L.p. |
| 240-505 | Bethesda | Montgomery | Cell Phone | Omnipoint Communications Ca... |
| 240-506 | Gaithersburg | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-508 | Upper Marlboro | Prince Georges | Cell Phone | Nextel Communications, Inc. |
| 240-510 | Upper Marlboro | Prince Georges | Landline | Xo Maryland, Llc |
| 240-514 | Rockville | Montgomery | Landline | Us Lec Of Maryland, Inc. |
| 240-515 | Capitol Heights | Prince Georges | Cell Phone | New Cingular Wireless Pcs,... |
| 240-520 | Rosedale | Baltimore | Cell Phone | Sprint Spectrum L.p. Md |
| 240-522 | Cumberland | Allegany | Cell Phone | Sprint Spectrum L.p. |
| 240-523 | La Plata | Charles | Landline | Xo Maryland, Llc |
| 240-524 | Clinton | Prince Georges | Landline | Global Naps South, Inc. Md |
| 240-525 | Wilmette | Cook | Landline | Global Naps South, Inc. Md |
| 240-527 | Hagerstown | Washington | Landline | Verizon Maryland, Inc. |
| 240-529 | Frederick | Frederick | Landline | Verizon Maryland, Inc. |
| 240-533 | Martinsburg | Berkeley | Landline | Teleport Communications Gro... |
| 240-535 | Silver Spring | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-536 | Fort Washington | Prince Georges | Landline | Global Naps South, Inc. Md |
| 240-538 | Lexington Park | Saint Marys | Landline | Xo Maryland, Llc |
| 240-542 | Greenbelt | Prince Georges | Landline | Us Lec Of Maryland, Inc. |
| 240-543 | Poolesville | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-544 | Bowie | Prince Georges | Landline | Us Lec Of Maryland, Inc. |
| 240-545 | Upper Marlboro | Prince Georges | Landline | Us Lec Of Maryland, Inc. |
| 240-547 | Laurel | Prince Georges | Landline | Level 3 Communications, Llc... |
| 240-548 | Washington | District Of Columbia | Landline | Allegiance Telecom, Inc. Md |
| 240-553 | Greenbelt | Prince Georges | Landline | Allegiance Telecom, Inc. Md |
| 240-554 | Annapolis Junction | Howard | Landline | Allegiance Telecom, Inc. Md |
| 240-556 | Bowie | Prince Georges | Landline | Paetec Communications, Inc.... |
| 240-558 | Silver Spring | Montgomery | Landline | Cavalier Telephone Midatla... |
| 240-560 | Silver Spring | Montgomery | Landline | Xo Maryland, Llc |
| 240-565 | Kensington | Montgomery | Cell Phone | Omnipoint Communications Ca... |
| 240-566 | Frederick | Frederick | Landline | Verizon Maryland, Inc. |
| 240-567 | Silver Spring | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-568 | Laurel | Prince Georges | Landline | Verizon Maryland, Inc. |
| 240-573 | Upper Marlboro | Prince Georges | Landline | Global Crossing Local Servi... |
| 240-575 | Frederick | Frederick | Landline | Level 3 Communications, Llc... |
| 240-577 | La Plata | Charles | Cell Phone | Cellco Partnership Dba Veri... |
| 240-580 | Cumberland | Allegany | Cell Phone | Nextel Communications, Inc. |
| 240-581 | Laurel | Prince Georges | Landline | Paetec Communications, Inc.... |
| 240-582 | Hyattsville | Prince Georges | Landline | Verizon Maryland, Inc. |
| 240-593 | Bowie | Prince Georges | Cell Phone | Omnipoint Communications Ca... |
| 240-595 | Washington | District Of Columbia | Cell Phone | Cellco Partnership Dba Veri... |
| 240-597 | Rockville | Montgomery | Landline | Global Naps South, Inc. Md |
| 240-599 | Gaithersburg | Montgomery | Landline | Broadwing Communications. L... |
| 240-601 | Temple Hills | Prince Georges | Cell Phone | Sprint Spectrum L.p. |
| 240-602 | Silver Spring | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-603 | Silver Spring | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-604 | Silver Spring | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-605 | District Heights | Prince Georges | Cell Phone | Sprint Spectrum L.p. |
| 240-606 | Laurel | Prince Georges | Cell Phone | Sprint Spectrum L.p. |
| 240-607 | Waldorf | Charles | Landline | Global Crossing Local Servi... |
| 240-616 | Greenbelt | Prince Georges | Landline | Mci Worldcom Communications... |
| 240-619 | Suitland | Prince Georges | Landline | Mci Worldcom Communications... |
| 240-620 | Laurel | Howard | Landline | Mci Worldcom Communications... |
| 240-623 | Gaithersburg | Montgomery | Landline | Unknown |
| 240-625 | Hagerstown | Washington | Cell Phone | Nextel Communications, Inc. |
| 240-626 | Frederick | Frederick | Cell Phone | Sprint Spectrum L.p. |
| 240-627 | Rockville | Montgomery | Landline | Global Crossing Local Servi... |
| 240-629 | Frederick | Frederick | Landline | Verizon Maryland, Inc. |
| 240-631 | Gaithersburg | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-632 | Gaithersburg | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-638 | Silver Spring | Montgomery | Landline | Broadwing Communications. L... |
| 240-643 | Bowie | Prince Georges | Cell Phone | Omnipoint Communications Ca... |
| 240-644 | Bethesda | Montgomery | Landline | Xo Maryland, Llc |
| 240-645 | Silver Spring | Montgomery | Landline | Xo Maryland, Llc |
| 240-646 | Laurel | Prince Georges | Landline | Cavalier East Llc Md |
| 240-654 | Gaithersburg | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-662 | Silver Spring | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-667 | Hyattsville | Prince Georges | Landline | Global Crossing Local Servi... |
| 240-668 | Germantown | Montgomery | Landline | Starpower Communications, L... |
| 240-669 | Silver Spring | Montgomery | Landline | Comcast Phone Of Northern M... |
| 240-671 | Lanham | Prince Georges | Cell Phone | Sprint Spectrum L.p. |
| 240-672 | Rockville | Montgomery | Cell Phone | Cellco Partnership Dba Veri... |
| 240-674 | Frederick | Frederick | Cell Phone | Nextel Communications, Inc. |
| 240-675 | Sharpsburg | Washington | Cell Phone | New Cingular Wireless Pcs,... |
| 240-676 | Lanham | Prince Georges | Cell Phone | Cellco Partnership Dba Veri... |
| 240-678 | Silver Spring | Montgomery | Cell Phone | Cellco Partnership Dba Veri... |
| 240-681 | Brandywine | Prince Georges | Landline | Atx Telecommunications Serv... |
| 240-682 | Waldorf | Charles | Landline | Starpower Communications, L... |
| 240-683 | Gaithersburg | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-684 | Greenbelt | Prince Georges | Landline | Verizon Maryland, Inc. |
| 240-685 | Lanham | Prince Georges | Landline | Global Crossing Local Servi... |
| 240-686 | Germantown | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-687 | Upper Marlboro | Prince Georges | Cell Phone | Cellco Partnership Dba Veri... |
| 240-688 | Silver Spring | Montgomery | Cell Phone | Cellco Partnership Dba Veri... |
| 240-691 | Bowie | Prince Georges | Landline | Global Crossing Local Servi... |
| 240-694 | Bethesda | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-695 | Suitland | Prince Georges | Landline | Verizon Maryland, Inc. |
| 240-696 | Hyattsville | Prince Georges | Landline | Level 3 Communications, Llc... |
| 240-699 | Frederick | Frederick | Landline | Verizon Maryland, Inc. |
| 240-715 | Rockville | Montgomery | Landline | Global Crossing Local Servi... |
| 240-720 | Gaithersburg | Montgomery | Landline | Global Crossing Local Servi... |
| 240-722 | Cumberland | Allegany | Landline | Global Crossing Local Servi... |
| 240-723 | Upper Marlboro | Prince Georges | Cell Phone | Cellco Partnership Dba Veri... |
| 240-724 | Cumberland | Allegany | Landline | Cavalier East Llc Md |
| 240-725 | Lexington Park | Saint Marys | Landline | Verizon Maryland, Inc. |
| 240-727 | Ridgeley | Mineral | Cell Phone | New Cingular Wireless Pcs,... |
| 240-731 | Gaithersburg | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-733 | Hagerstown | Washington | Landline | Unknown |
| 240-737 | Lanham | Prince Georges | Landline | Cavalier East Llc Md |
| 240-743 | Bethesda | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-744 | Bethesda | Montgomery | Landline | Broadwing Communications. L... |
| 240-747 | Rockville | Montgomery | Landline | Cavalier East Llc Md |
| 240-750 | Durham | Durham | Cell Phone | New Cingular Wireless Pcs,... |
| 240-751 | Gaithersburg | Montgomery | Landline | Telcove Operations, Inc. Md |
| 240-752 | Silver Spring | Montgomery | Landline | Telcove Operations, Inc. Md |
| 240-753 | Clinton | Prince Georges | Landline | Telcove Operations, Inc. Md |
| 240-755 | Clarksville | Howard | Landline | Comcast Phone Of Northern M... |
| 240-764 | Hyattsville | Prince Georges | Landline | Xo Maryland, Llc |
| 240-765 | Upper Marlboro | Prince Georges | Landline | Xo Maryland, Llc |
| 240-766 | Fort Washington | Prince Georges | Landline | Xo Maryland, Llc |
| 240-770 | Hyattsville | Prince Georges | Landline | Comcast Phone Of Northern M... |
| 240-773 | Rockville | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-776 | La Plata | Charles | Landline | Broadwing Communications. L... |
| 240-777 | Rockville | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-778 | Rockville | Montgomery | Landline | Xo Maryland, Llc |
| 240-779 | Olney | Montgomery | Landline | Cavalier East Llc Md |
| 240-780 | Gaithersburg | Montgomery | Landline | Broadwing Communications. L... |
| 240-782 | Laurel | Prince Georges | Landline | Global Crossing Local Servi... |
| 240-783 | Bethesda | Montgomery | Landline | Mte, Inc. Dba Mte Paging Ne... |
| 240-784 | Silver Spring | Montgomery | Cell Phone | Omnipoint Communications Ca... |
| 240-786 | Laurel | Prince Georges | Landline | Broadwing Communications. L... |
| 240-787 | Cheltenham | Prince Georges | Landline | Broadwing Communications. L... |
| 240-788 | Suitland | Prince Georges | Landline | Broadwing Communications. L... |
| 240-790 | Beltsville | Prince Georges | Landline | Broadwing Communications. L... |
| 240-793 | Frederick | Frederick | Cell Phone | Nextel Communications, Inc. |
| 240-794 | Great Mills | Saint Marys | Landline | Broadwing Communications. L... |
| 240-812 | Frederick | Frederick | Landline | Global Crossing Local Servi... |
| 240-813 | Gaithersburg | Montgomery | Landline | Atx Telecommunications Serv... |
| 240-818 | Smithsburg | Washington | Landline | Verizon Maryland, Inc. |
| 240-821 | Silver Spring | Montgomery | Landline | Lightwave Communications, L... |
| 240-823 | Upper Marlboro | Prince Georges | Landline | Xo Maryland, Llc |
| 240-824 | Silver Spring | Montgomery | Landline | Unknown |
| 240-826 | Rockville | Montgomery | Landline | Verizon Maryland, Inc. |
| 240-832 | Fort Washington | Prince Georges | Cell Phone | Nextel Communications, Inc. |
| 240-833 | Rockville | Montgomery | Landline | Xo Maryland, Llc |
| 240-834 | Washington | District Of Columbia | Landline | Unknown |
| 240-838 | Suitland | Prince Georges | Cell Phone | Omnipoint Communications Ca... |
| 240-839 | Silver Spring | Montgomery | Cell Phone | Cellco Partnership Dba Veri... |
| 240-840 | Rockville | Montgomery | Landline | Unknown |
| 240-843 | Greenbelt | Prince Georges | Landline | Allegiance Telecom, Inc. Md |
| 240-845 | Beltsville | Prince Georges | Landline | Xo Maryland, Llc |
| 240-846 | Gaithersburg | Montgomery | Landline | Xo Maryland, Llc |
| 240-848 | Gaithersburg | Montgomery | Cell Phone | Nextel Communications, Inc. |
| 240-855 | Gaithersburg | Montgomery | Cell Phone | Sprint Spectrum L.p. |
| 240-857 | Andrews Afb | Prince Georges | Landline | Tw Telecom Of Maryland Llc... |
| 240-863 | Silver Spring | Montgomery | Landline | Tw Telecom Of Maryland Llc... |
| 240-864 | Rockville | Montgomery | Landline | Cavalier East Llc Md |
| 240-865 | Crofton | Anne Arundel | Landline | Level 3 Communications, Llc... |
| 240-868 | Silver Spring | Montgomery | Landline | Cavalier East Llc Md |
| 240-876 | Rockville | Montgomery | Cell Phone | Nextel Communications, Inc. |
| 240-880 | Rockville | Montgomery | Landline | Broadwing Communications. L... |
| 240-882 | Upper Marlboro | Prince Georges | Cell Phone | Nextel Communications, Inc. |
| 240-883 | Olney | Montgomery | Landline | Broadwing Communications. L... |
| 240-888 | Kensington | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-892 | Upper Marlboro | Prince Georges | Landline | Broadwing Communications. L... |
| 240-893 | Silver Spring | Montgomery | Cell Phone | New Cingular Wireless Pcs,... |
| 240-895 | Lexington Park | Saint Marys | Landline | Verizon Maryland, Inc. |
| 240-897 | Clinton | Prince Georges | Landline | Broadwing Communications. L... |
| 240-898 | Hyattsville | Prince Georges | Landline | Broadwing Communications. L... |
| 240-899 | Washington | District Of Columbia | Cell Phone | Omnipoint Communications Ca... |
| 240-912 | Gaithersburg | Montgomery | Landline | Us Lec Of Maryland, Inc. |
| 240-925 | Mechanicsville | Saint Marys | Cell Phone | Cellco Partnership Dba Veri... |
| 240-929 | Bowie | Prince Georges | Landline | Cavalier East Llc Md |
| 240-938 | Columbia | Howard | Cell Phone | Omnipoint Communications Ca... |
| 240-949 | Reston | Fairfax | Landline | Cavalier East Llc Md |
| 240-965 | Greenbelt | Prince Georges | Landline | Paetec Communications, Inc.... |
| 240-979 | Cumberland | Allegany | Landline | Level 3 Communications, Llc... |
| 240-986 | Catonsville | Baltimore | Landline | Xo Maryland, Llc |
| 240-988 | Bowie | Prince Georges | Cell Phone | Sprint Spectrum L.p. |
| 240-993 | Newport News | Newport News City | Landline | Xo Maryland, Llc |
| 240-994 | Gaithersburg | Montgomery | Cell Phone | Cellco Partnership Dba Veri... |
| 240-997 | Bowie | Prince Georges | Cell Phone | Cellco Partnership Dba Veri... |
| 240-998 | Capitol Heights | Prince Georges | Landline | Unknown |