5 of the best mountain bike trails in the USA! With the USA’s vast landscape and numerous world-renowned national parks, it’s no surprise that cyclists flock to test themselves, or simply enjoy the beauty of the scenery on US mountain bike trails. This post includes the Big Sur in California; the Shark Valley Mountain Bike Trail in Miami; the Banks Vernonia Mountain Bike Trail in Oregon; the Little Pan Loop, Black Canyon Trail in New River, Arizona (also known as the Lollipop Loop); and the Carriage Trails in the Acadia National Park in Maine.