[peckrob]

Alaska has lots of places that are only reachable by air or by extremely difficult overland routes that may only be passable during certain times of year.

Supai, Arizona [0] is only accessible by helicopter or an 8-mile hike from the nearest road.

[0] https://en.wikipedia.org/wiki/Supai,_Arizona

[sib]

And it's worth every bit of the journey to see the waterfalls.

https://fernweh.photo/2016/11/19/supai-arizona/

The helicopter "pad" and the hiking trailhead are themselves many miles from the nearest town. Supai is often claimed to be the most remote town in the 48 contiguous states.