Lake Clark National Park and Preserve
Lassen Volcanic National Park
Mammoth Cave National Park
Mesa Verde National Park
Mount Rainier National Park
North Cascades National Park
Olympic National Park

Other Park Units L-O

Lake Mead National Recreation Area
Lake Powell (Glen Canyon National Recreation Area)
Lava Beds National Monument
Little Bighorn Battlefield National Monument
Manzanar National Historic Site
Marsh-Billings-Rockefeller National Historical Park
Mojave National Preserve
Montezuma Castle National Monument
Mount Rushmore National Memorial
Muir Woods National Monument
Natchez Trace Parkway (and National Scenic Trail)
National Mall and Memorial Parks
Natural Bridges National Monument
New River Gorge National River
Niobrara National Scenic River
Oregon Caves National Monument and Preserve
Organ Pipe Cactus National Monument
Ozark National Scenic Riverways