The US in general has much less cell service than you might think. I'm on a major carrier, I get 1 bar at home, there are places in my neighborhood that effectively have none, and I'm within a few miles of state forest where there is definitely no service.

If you never leave a city or major transportation routes, you might not realize how much "dark" space there is. Those red maps the mobile service providers like to promote seem to me to be extremely deceptive.