Cool! We were in Ketchum and Stanley in July. It is a magnificent place.
I’m very surprised to see that Mont Meganticmin Quebec is the only other recognized dark place in the Americas. That spot was made famous by Arnold’s march on Quebec that ultimately foiled the British plans to cut the New England colonies off from their brethren to the south.
Maybe it’s dark in Megantic because the sun never shines there.
The sky in the Eastern Sierra of California extending eastward to Tonopah, Nevada is also one of the darkest places in America. Apparently unrecognized as such by the powers that be, I can see "interstellar dust clouds" of the Milky Way from here easily.