#1The sun sets behind large red and white towers of sandstone.

Zion

UT

Very CrowdedDark Sky

Red cliffs rise 2,000 feet above the Virgin River, where Angels Landing's chain climb and The Narrows' slot canyon wade draw crowds.

#2The Desert View Watchtower looms 70 feet into the air over a vast and dramatic view of the canyon.

Grand Canyon

AZ

Moderate CrowdsDark Sky

The Colorado River carved through two billion years of rock to create a chasm one mile deep and 277 miles long at the South Rim.

#3Ptarmigan in winter coat

Rocky Mountain

CO

Busy

Trail Ridge Road crosses the Continental Divide at 12,183 feet. Below, 300 miles of trails connect glacial lakes to 14,259-foot Longs Peak.

#4Snow blankets a red rock landscape of tall rock spires beneath an early morning sky

Bryce Canyon

UT

Very CrowdedDark Sky

Earth's densest hoodoo forest where the Navajo Loop drops you between orange spires so narrow you'll touch both walls at 8,000 feet.

#5a broad, red arch with rock pinnacles in the background

Arches

UT

Very CrowdedDark Sky

Over 2,000 natural stone arches carved from red sandstone—the world's highest concentration—including the iconic Delicate Arch.

#6A hiker stands beside Hickman Bridge, a natural sandstone bridge

Capitol Reef

UT

Busy

A hundred-mile wrinkle in the earth where sandstone cliffs fold into hidden canyons and pioneer orchards still grow beneath Capitol Dome.

#7A flowering fishhook pincushion cactus

Saguaro

AZ

Very CrowdedDark Sky

Giant saguaros, some 200 years old and 40 feet tall, frame both sides of Tucson in the densest stands of these iconic cacti anywhere.

#8shallow pools with a double rainbow in the background

Canyonlands

UT

Moderate CrowdsHidden GemDark Sky

Four districts carved by the Colorado River—from Island in the Sky's overlooks to The Maze's backcountry spanning canyons larger than LA.

#9Aerial of white sand dunes.

White Sands

NM

BusyHidden GemDark Sky

The world's largest gypsum dunefield covers 275 square miles where white sand dunes shift up to 30 feet per year and swallow ecosystems.

#10Century Plant Agave

Big Bend

TX

ComfortableHidden GemDark Sky

Big Bend protects 1,200 square miles where the Chisos Mountains rise from desert. Over 450 bird species recorded—more than any park.

#11Sunset lights up the Painted Desert Inn National Historic Landmark west side.

Petrified Forest

AZ

Moderate CrowdsHidden Gem

Twenty-eight miles of road through technicolor badlands where 225-million-year-old trees turned to stone sprawl wider than cars.

#12Park visitors visiting a cliff dwelling

Mesa Verde

CO

Moderate CrowdsHidden GemDark Sky

Seven hundred Ancestral Pueblo dwellings are carved into sandstone alcoves, including the 150-room Cliff Palace accessible by ladder.

#13Photo of the Big Room with trail

Carlsbad Caverns

NM

Moderate CrowdsHidden Gem

A 600-foot limestone cavern beneath the Chihuahuan Desert, carved by sulfuric acid rather than water, where 400,000 bats spiral out at dusk.

#14Girls Sand Sledding

Great Sand Dunes & Preserve

CO

Moderate CrowdsHidden GemDark Sky

North America's tallest sand dunes rise 750 feet against the Sangre de Cristo Mountains, with alpine lakes and tundra at 13,000 feet above.

#15Black Canyon near Painted Wall

Black Canyon Of The Gunnison

CO

Moderate CrowdsHidden Gem

Gunnison River carved North America's steepest gorge through 1.7-billion-year-old rock, with 2,000-foot walls that trap the sun.

#16the slat flats become flooded during monsoon months after large rain events.

Guadalupe Mountains

TX

ComfortableHidden Gem

Texas's highest peaks rise from a 265-million-year-old fossil reef in the Chihuahuan Desert, holding more species than any Texas park.