Do It Yourself RV had an article about finding dark skies for seeing the stars – almost a rare commodity nowadays. The article referenced the International Dark Skies Association. Quite a few are in the U.S. Here’s a map where you can find a location. http://www.darksky.org/idsp/finder/
This map shows the positions of locations designated as part of the International Dark Sky Places Program only. It is not a comprehensive map of dark site