Eight parks, one state, and more than half of them unreachable by road.
Alaska is its own region for the same reason it is its own everything: scale. These eight parks cover more ground than the other 55 combined, and the grouping needs no justification beyond a map.
What does need saying is how differently they work. Four of the eight have no road access at all. Getting to Gates of the Arctic or Kobuk Valley means chartering a bush plane. Those two are the least visited national parks in the country, at roughly 14,900 and 7,800 visits a year, which is less traffic in twelve months than the Grand Canyon sees before lunch.
This is the one region nobody argues with.