5G is now "nationwide," although with the very different approaches to 5G, you're going to have very different experiences in different places.
Verizon has fast, high-band 5G in parts of 34 cities, with online coverage maps here.
Verizon has 5G in more than 30 cities nationwide
New T-Mobile currently has a slow nationwide low-band 5G network that covers most of the country; Sprint mid-band in 10 cities, with a coverage finder here; and T-Mobile high-band in seven cities (the ones listed in that link, plus Miami).
AT&T has slow low-band across about a third of the country and high-band in 35 cities, which it doesn't give maps for and is unnecessarily confusing about the coverage of. It calls the low-band "5G" and the high-band "5G+." The company has low-band maps and a high-band city list here.
Verizon 5G is fast, if you can find itWhich 5G Phones Are Coming Out?
We're currently on the second generation of 5G phones. The first generation, using the Qualcomm X50 modem, didn't support the US low-band networks or DSS, and overheated during the summer. We do not recommend those any more. The second generation, using the X55 modem, appears to be doing better, but we haven't tested them in summer yet.
