Picture Lake is not technically in North Cascades National Park but the Mount Shuksan in the distance is. Getting here from the park requires a 2.5 hour drive.
According to the National Park Service, there are over 500 lakes and ponds located within the boundaries of North Cascades National Park. The best are Ross Lake, Lake Chelan, and Diablo Lake.
Stehekin is a naturally blessed, intimately secluded, small community located on the shores of the third deepest lake in the United States, Lake Chelan.
I'll admit when I first saw a photo of this place I thought it was a hoax, like something from Northern Italy or Switzerland - but it's completely real and amazing.