Petrified Forest National Park
Pinnacles National Park
Redwood National Park
Rocky Mountain National Park
Saguaro National Park
Sequoia National Park
Shenandoah National Park

Other Park Units P-S

Padre Island National Seashore
Pearl Harbor
Pictured Rocks National Lakeshore
Point Reyes National Seashore
Rainbow Bridge National Monument
Rock Creek Park
Saint Croix National Scenic Riverway
San Antonio Missions National Historical Park
Sleeping Bear Dunes National Lakeshore
Statue of Liberty National Monument
Sunset Crater Volcano National Monument