We have found that almost any place that is interesting to hike, and especially backpack, does not have cell phone reception, or at best lousy cell phone reception.
To which I say hallelujah! I do not want to be in touch with the world when I am hiking. I do not want to keep au courant with my e-mail on the trail, or find out what the latest mess is on and near that Hill 21 miles from my house.
I wonder what percentage of good hiking and backpacking territory has lousy or no cell-phone coverage. So that there is a chance that this question can be answered, I ask about coverage in the US National Parks. That is, I am using the National Parks as a proxy for the greater great outdoors. However, if anyone has information that is not confined to the US National Parks, that would be welcome.