Cellular Maps.com
On-Network Cellular Coverage Comparison
The most basic coverage (Talk, Text & 3G Data or better) of the Top 5 largest US networks, listed alphabetically. Does NOT include roaming partners unless indicated.
AT&T Coverage, 2018
AT&T Coverage
AT&T Hawaii Coverage AT&T PR + VI Coverage
Alaska Coverage Hawaii Coverage Puerto Rico & US VI
Sprint Coverage, 2018
Sprint Coverage
Sprint HI Sprint PR+VI
Hawaii Coverage Puerto Rico & US Virgin Islands

Includes coverage supplied by some roaming partners. Areas shown as, "Extended..." can be included in your Sprint plan, but Sprint notes "not all services may be available," in those areas.  
T-Mobile Coverage, 2018
This map shows all of T-Mobile's own coverage including 600 and 700 MHz channels which requires a phone compatible with these new bands. Click to Zoom In.
T-Mobile Coverage
Hawaii PR & US VI

US Cellular Coverage, 2017

Verizon Wireless Coverage, 2018
Verizon Coverage
Alaska Coverage HI, PR & US VI