Coverage map
Wireless carriers provide coverage maps on their Web sites and in stores where their products are sold. Often these maps show very general coverage for entire regions. These maps usually carry the disclaimer that they are provided for informational purposes only and that actual coverage may vary. There may be holes where the carrier has not located antennas or where the topography causes dead spots.
There is no guarantee that your phone will work in an area just because it is included on a carrier's coverage map. Regions where towers are few and far between may technically be included in your home area, but the quality of your calls may be so poor that you can't use your phone. Although carriers attempt to design their networks to eliminate dropped calls, busy signals, and dead zones, no network is perfect, so coverage breaks within the general coverage areas are still possible. Specific and/or updated information may not be available in maps provided by carriers, since coverage is frequently changing.