What cell phone company works best in out of the way areas?

My dad wants a cell phone but lives in rural Indiana (southeast Indiana, northwest of Louisville, 1 hour west of Cincinnati) my sprint phone stops once I turn of the highway. Suggestions? Also I have heard about a booster that could be put in his house, know anything about that?

Verizon Wireless has the largest footprint in the US. My parents get great signal in the rural area they live in. You might want to call up customer service for different companies, give them the zip code, and see what they provide in that area.

I checked my Verizon mapping and you'd have digital service in that area. Possible broadband connection depending upon how close to Louisville.