Established in 1916 to preserve the country's natural and cultural resources, the U.S. National Park Service (NPS) has been 'entrusted with the care of U.S. National Parks' ever since.
Today, the NPS protects more than 400 parks across the USA's 50 states and five territories, which are visited by more than 325 million people each year.
The Great American Outdoors Day gives free national park entry to visitors on 5 August each year.
Five of the USA's more lesser-known protected areas are :
Theodore Roosevelt National Park, North Dakota
Theodore Roosevelt came to Dakota Territory to hunt bison in 1883 and this helped shape a conservation policy that the USA still benefits from today.
After becoming president in 1901, Roosevelt protected 230 million acres of public land.
In 1947, he established the Theodore Roosevelt National Memorial Park.
This takes in the rugged Badlands, where bison roam freely along deer, elk, wild horses, longhorns and coyotes.
www.nps.gov/thro/index.htm and www.ndtourism.com
Hot Springs National Park, Arkansas
Hot Springs National Park is known for its 47 thermal springs and cultural past.
The nation's oldest national reservation, established in 1832, was designated a National Park in 1921.
It features more than 30 miles of hiking trails through the Ouachita Mountains, scenic drives, and campsites at Gulpha Gorge Recreation Area & Campground.
Hot Springs itself is a homage to the "American Spa" of the 20th century.
The grand architecture of the nine historic bathhouses have been drawing people here for hundreds of years.
www.nps.gov/hosp/index.htm and www.arkansas.com
Cuyahoga Valley National Park, Ohio
Located near to the urban areas of Cleveland and Akron,the Cuyahoga Valley National Park is a refuge for native plants and wildlife and provides routes of discovery for visitors.
The winding Cuyahoga River (the "Crooked River") gives way to gives way to 33,000 acres of deep forests, rolling hills, and open farmlands.
It was established as a national recreation area in 1974 and as a national park in 2000.
Remains of the Ohio & Erie Canal, which travelled through the valley in the 19th and early 20th centuries, offer a glimpse into the history of how the country was transformed.
www.nps.gov/cuva and www.ohio.org
Indiana Dunes National Park, Indiana
Designated the country's 61st National Park in February 2019, the Indiana Dunes National Park borders 24 kilometres of the southern shore of Lake Michigan.
Large sand dunes, located beyond the shoreline, have taken thousands of years to form, and tower 61 metres above Lake Michigan.
A wide range of habitats are found in the park which provide homes for many types of plants and animals.
www.nps.gov/indu/index.htm and www.visitindiana.com
Mt. Rainier National Park, Washington
Mount Rainier, rises to 4392 metres above sea level in the Cascade Mountain Range, is an active volcano and the most glaciated peak in the contiguous USA, spawning five major rivers.
Mountaineering enthusiasts can test their climbing skills in Mount Rainier National Park and there are 400 kilometres of hiking trails.
On the 150-kilometre long Wonderland Trail that circles Mount Rainier, hikers could spot a black bear or mountain lion in the forests, valleys, and alpine areas.
www.nps.gov/mora/index.htm and www.experiencewa.com