It is a mystery as to how these national parks remained unnoticed and how visitors and travelers overlooked these hidden gems.

Although each of the nation's national parks has unique treasures and experiences to offer visitors, some are more well-known than others. The National Park Service released a list of the parks with the least amount of visitors in 2021. These national parks are still hidden gems that are well worth the trip, despite their low visitor numbers.

1. ALASKA: Gates of the Arctic National Park and Preserve

Alaska's Gates of the Arctic National Park and Preserve is for the traveler looking to truly get away from it all, with no roads or trails, only the elegant landscape carved by glaciers. It was the least-visited national park of the year in 2021 with only 7,362 visitors. The region is one of the planet's last truly wild places, according to park representatives.

2. AMERICAN SAMOA: National Park of American Samoa

The National Park of American Samoa is situated about 2,600 miles due southwest of Hawaii. According to the National Park Service, it is one of the least accessible national parks, receiving only 8,495 visitors in 2021.

The park is home to a staggering 991 species of fish, which visitors can spot. Those who are fortunate enough to travel there are rewarded with stunning views of the crystal-clear sea, a view of teeming aquatic life, and coral sand beaches.

On land, there is a sizable network of trails that offer breathtaking views for hikers, as well as a visitors center and a special homestay program where visitors can learn more about Samoan culture.

3. WASHINGTON: North Cascades National Park

North Cascades National Park, which is three hours from Seattle, offers the greatest glacier views in the United States that are outside of Alaska. One of the snowiest locations on earth is the North Cascades National Park Service Complex. Beginner hikers can take short, picturesque strolls in the alpine scenery, while more experienced hikers can take longer trails that pass by glaciers.

4. MICHIGAN: Isle Royale National Park

In the middle of Lake Superior, on a remote island, is Isle Royale National Park. Only boats or seaplanes are permitted to enter the national park, and transportation can be arranged from nearby locations. When visitors arrive at the park, they will find forests, backcountry trails, rocky shorelines, and 400 satellite islands that can be explored by boat. Considering that sunken shipwrecks have remained in place and Lake Superior's chilly waters make it an ideal place for scuba diving, Travel + Leisure reports.

5. FLORIDA: Dry Tortugas National Park,

The island at the southernmost tip of the United States is a truly remarkable place, and Dry Tortugas National Park encapsulates its history and natural splendors. It is home to a wide variety of unusual birds and has the only regular sooty tern nesting location in the United States on Bush Key, close to Fort Jefferson. Dry Tortugas claims that visits are a once-in-a-lifetime experience thanks to the colorful coral reefs, exotic tropical fish, nesting sea turtles, and underwater wonders.