Rocky Mountain National Park, Colorado
While the skies above Rocky Mountain National Park can be subjected to light pollution from the nearby metropolitan areas of Boulder and Denver, they still offer up some spectacular shows for travelers. Because the area allows easy access to high altitudes, it is possible to see some of the darkest skies in the United States. The 265,873-acre park boasts its highest elevation at Longs Peak at 14,259 feet. Park officials recommend winter nights as the optimal time for stargazing, as atmospheric conditions reveal the stars at their brightest.