There are currently 63 National Parks in the US. Of those, 51 are in the 48 contiguous states, plus eight in Alaska, two in Hawaii, one in American Samoa, and one in US Virgin Islands. We have now visited 52 parks; the 51 contiguous plus Virgin Islands; the remaining 11 will be more tricky to visit, but we do want to get to them in due course.
This is a good occasion to consider how we feel about the 52 parks. And what better way to evaluate them than as a tier list, which rates things as S (super), A, B, C, D, and F (fail).
Here’s how we rated the parks:

Or in text (click or tap the links to see my blog posts about each park):
S tier: Arches, Grand Canyon, Joshua Tree, Olympic, and Yellowstone. Best of the best.
A tier: Badlands, Big Bend, Bryce Canyon, Death Valley, Dry Tortugas, Everglades, Grand Teton, Isle Royale, Virgin Islands, Yosemite, Zion. All very good parks.
B tier: Acadia, Black Canyon of the Gunnison, Canyonlands, Capitol Reef, Carlsbad Caverns, Crater Lake, Glacier, Kings Canyon, Mesa Verde, Mount Rainier, North Cascades, Petrified Forest, Pinnacles, Redwood, Saguaro, Sequoia, Theodore Roosevelt, Voyageurs, Wind Cave. Still pretty good, but not overly remarkable.
C tier: Biscayne, Channel Islands, Great Basin, Great Sand Dunes, Great Smoky Mountains, Guadalupe Mountains, Hot Springs, Lassen Volcanic, Rocky Mountain, Shenandoah, White Sands. Fine parks, but mostly one-trick-ponies.
D tier: Congaree, Gateway Arch, Mammoth Cave, New River Gorge. Kinda boring, not really worthy of being National Parks.
F tier: Cuyahoga Valley, Indiana Dunes. Lame, shouldn’t be National Parks.
Of course, these rankings are very subjective, and may change as we explore them more. But that’s how we currently rate them.