i'm not sure how up to date this is but hopefully it helps: http://tinyurl.com/cuvn9sl

For what it's worth I understand that most cell phone companies lease from each other with the most used network being AT&T. A lot of the smaller companies don't have any towers at all. I could be wrong but this is the way it was explained to me by someone who's job was working on these towers. I would think you could call Verizon and ask them who they lease from.