You must find a balance between dark skies and accessibility. Mountaintop observatories like those on Mauna Kea, Hawaii, offer unparalleled views of the sky, but most will never visit.
For amateur stargazers, the best locations are the Dark-Sky Parks and Reserves defined by the International Dark-Sky Association.
The largest of these are the Death Valley National Park, California, USA and the Aoraki/Mount Cook Park on New Zealand’s South Island, but there are now three in the United Kingdom as well: Northumberland National Park, Brecon Beacons National Park and Galloway Forest Park.
Answered by Giles Sparrow