Wikipedia's map is wrong. The "border" includes international airports. There is very little of the population that is not within 100 miles of this "border."

The map also does not show Hawai'i, which would be one green blob, there is no part of Hawai'i not 100 miles from the border. All of the New England states are similarly small enough to be completely covered, even by the erroneous picture of the physical border.

You basically get a few, mostly uninhabited spots out in the West that aren't covered.