Yellowstone might be the oldest and the best known, but the United States is full of other incredible national parks both on and off the beaten track. As the USA's National Park Service prepares to celebrate its centenary next year, PAM JONES takes a look at some of the most visited and lesser known parks in the American wilderness.
• ALASKA
Alaska has more national parks than any other state in the United States, and it's no wonder. Huge tracts of wilderness fill the state and, as well as Alaska's eight national parks, there are numerous other national state parks, historic parks, preserves and recreation areas.
Denali National Park, with its massive Mount McKinley (now also known as Mount Denali) is probably the best known, but be bold and explore elsewhere as well.
You can travel for miles, or try one of the more easily accessed parks for size: the Kenai Fjords National Park is only a two-and-a-half hour drive from Anchorage, and easily accessed from the southeastern town of Seward.
• UTAH
Running a close second, the state of Utah has five national parks - the most in any American state except for Alaska.
Zion, Bryce Canyon, Capital Reef, Canyonlands and Arches national parks are promoted as the "Mighty 5'' and all boast brilliant red-rock sunsets and numerous hiking trails.
The out-of-this-world landscapes in the much-visited Bryce Canyon National Park have been carved by wind and water, and some high-profile personalities have put their own stamp on the place too - the infamous outlaw Butch Cassidy roamed these parts and one of his hideout cabins is located nearby.
• MONTANNA
Glacier National Park in Montana is marketed as "Mother Nature's Best Work'' and its nickname is the "Crown of the Continent''.
There are various pathways through the different sides of the park, and popular hiking trails with cute names: The Iceberg Lake Trail, Hidden Lake Overlook Trail, Stoney Indian Pass Trail and Swiftcurrent Pass Trail will take you to the heart of the American wilderness.
• AMERICAN SAMOA
But for something entirely different, head to American Samoa. The US territory has one of the nation's 59 national parks, as well as a national marine sanctuary.
In the heart of the South Pacific, you can snorkel coral reefs, explore tropical forests and visit secluded villages.
With more than 950 species of fish and 250 species of coral it's an underwater delight, and the intrepid nature of getting to some of the islands adds to their charm and feeling of exclusivity.
• OREGON
In Oregon, Crater Lake might have had a full-on volcanic past, but it's now an unbelievably peaceful and beautiful centrepiece of the Crater Lake National Park. You can take boat tours on the lake or hike one of the many trails in the park.
The park is open year round but winter access is limited - the best access is usually from July to October.
• NEW MEXICO
And on a desert note, try the Carlsbad Caverns National Park, in New Mexico. Hidden beneath the surface is a network of caves formed when sulphuric acid dissolved the surrounding limestone to leave behind caverns of all sizes.
There are a variety of cave tours and self-guide options available, as well as a spectacular nature "show'' from the park's "Bat Flight'' programme.
From May to October at dusk, hundreds of thousands of Brazilian Free-tailed bats exit the cave on their nightly forage for food.