National Park Service Sites in Washington
Olympic National Park
Olympic and Mount Rainier National Parks were established years ago and are known around the world. North Cascades National Park isn't very old, is little developed and is considered by most folks to be primarily a wilderness park. Most folks visiting North Cascades will actually do their camping on the Ross Lake National Recreation Area as that is where virtually all of the developed campsites are.
Lake Chelan National Recreation Area is accessible only via floatplane or passenger ferry. And as a purist, I have to admit the Mount Baker National Recreation Area is not under National Park Service administration but under the administration of Mount Baker-Snoqualmie National Forest.
National Park Service Sites
Thornton Lakes in North Cascades National Park
Photo of North Cascades National Park courtesy of Walter Siegmund, CCA-by-SA 3.0 License
Map courtesy of Cartesia MapArt US Terrain