Here's a visual map of every US National Park.  How many US National Parks are there do you ask?  58.  If you're planning a road trip, having a visual map showing where everything's located will be a big help.  I made this map specifically so I could see which National Parks are near me when I travel to a certain state, with the idea that I can try to travel to more than just one park on each trip.  

Denali

Gates of the Arctic

Glacier Bay

Katmai

Kenai Fjords

Kobuk Valley

Lake Clark

Wrangell - St. Elias

American Samoa

Grand Canyon

Petrified Forest

Saguaro

Hot Springs

Channel Islands

Death Valley

Joshua Tree

Kings Canyon

Lassen Volcanic

Redwood

Sequoia

Yosemite

Black Canyon of the Gunnison

Great Sand Dunes

Mesa Verde

Rocky Mountain

Biscayne

Dry Tortugas

Everglades

Haleakala

Hawaii Volcanoes

Mammoth Cave

Acadia

Isle Royale

Voyageurs

Glacier

Yellowstone

Great Basin

Carlsbad Caverns

Great Smoky Mountains

Theodore Roosevelt

Cuyahoga Valley

Crater Lake

Congaree

Badlands

Wind Cave

Big Bend

Guadalupe Mountains

Virgin Islands

Arches

Bryce Canyon

Capitol Reef

Canyonlands

Zion

Shenandoah

Mount Rainier

North Cascades

Olympic

Grand Teton

Yellowstone