In the late Precambrian, the primordial ocean expanded, and the more recent Ocoee Supergroup rocks formed from the accumulation of eroding land mass onto the continental shelf.

[35] A report published in 2023 by the North Carolina Division of Air Quality indicates significant drops in emissions of sulfur dioxide, carbon monoxide, oxides of nitrogen, volatile organic compounds, and fine particulate matter.

[44] Plants and animals common in the country's Northeast have found suitable ecological niches in the park's higher elevations, while southern species find homes in the balmier lower reaches.

[48] The Albright Grove along the Maddron Bald Trail (between Gatlinburg and Cosby) is an accessible old-growth forest with some of the oldest and tallest trees in the entire range.

The dominant species include yellow birch (Betula alleghaniensis), basswood (Tilia americana), yellow buckeye (Aesculus flava), tulip tree (Liriodendron tulipifera; commonly called "tulip poplar"), silverbells (Halesia carolina), sugar maple (Acer saccharum), cucumber magnolia (Magnolia acuminata), shagbark hickory (Carya ovata), Carolina hemlock (Tsuga caroliniana) and eastern hemlock (Tsuga canadensis).

[56] The Southern Appalachian spruce–fir forest—also called the "boreal" or "Canadian" forest—is a relict of the ice ages, when mean annual temperatures in the Smokies were too cold to support a hardwood forest.

While the rise in temperatures between 12,500 and 6,000 years ago allowed the hardwoods to return, the spruce-fir forest has managed to survive on the harsh mountain tops, typically above 5,500 feet (1,700 m).

Many wildflowers grow in mountains and valleys, including bee balm, Solomon's seal, Dutchman's breeches, various trilliums, the Dragon's Advocate and even hardy orchids.

The reverse is true in autumn, when nearly bare mountaintops covered in rime ice (frozen fog) can be separated from green valleys by very bright and varied leaf colors.

[74] European wild boar, introduced as game animals in the early 20th century, thrive in southern Appalachia but are considered a nuisance because of their tendency to root up and destroy plants.

Species more typical of cooler climates, such as the raven, winter wren, black-capped chickadee, yellow-bellied sapsucker, dark-eyed junco, and Blackburnian, chestnut-sided, and Canada warblers, are found in the spruce-fir and northern hardwood zones.

[99][37] The firefly Photinus carolinus, whose synchronized flashing light displays occur in mid-June, is native to the Great Smoky Mountains with a population epicenter near Elkmont, Tennessee.

Surrounding towns—notably Gatlinburg, Pigeon Forge, Sevierville, and Townsend in Tennessee, and Cherokee, Sylva, Maggie Valley, and Bryson City in North Carolina—receive a significant portion of their income from tourism associated with the park.

[106] The AT enters the park atop Fontana Dam, and ascends a long ridge to the top of Brier Lick Knob at the Tennessee-North Carolina state line.

The extreme heat of the fires resulted in accelerated weathering and potential mass wasting of the exposed rock, and therefore access to the summit is no longer permitted for safety reasons.

Situated in a beech forest swag between Balsam High Top and Big Cataloochee Mountain, the Laurel Gap Shelter can accommodate up to 14 people per night.

At an elevation of 5,048 feet (1,539 m), it is the lowest gap in the crest of the mountains and is situated near the center of the park, on the Tennessee/North Carolina state line, halfway between Gatlinburg and Cherokee.

A section of U.S. Route 129 which runs along the western boundary of the park is known as the "Tail of the Dragon", due to its extremely curvy alignment, and is popular with motorcyclists and sports car enthusiasts.

[120] The increasing reliance upon agriculture during the Mississippian period (c. 900–1600 A.D.) lured Native Americans away from the game-rich forests of the Smokies and into the fertile river valleys on the outer fringe of the range.

Although much of the tribe was forced west along the Trail of Tears in 1838, a few—largely through the efforts of William Holland Thomas—managed to retain their land on the Qualla Boundary and today comprise the Eastern Band of Cherokee Indians.

While both Tennessee and North Carolina joined the Confederacy at the outbreak of the American Civil War in 1861, Union sentiment in the Great Smoky Mountains was much stronger relative to other regions in these two states.

[citation needed] Thomas' Legion crossed the Smokies in 1862 and occupied Gatlinburg for several months to protect saltpeter mines atop Mount Le Conte.

As timber resources in these regions became exhausted, and as the demand for lumber skyrocketed after the Civil War, entrepreneurs began looking for ways to reach the virgin forests of southern Appalachia.

[153][154] In the early 20th century, locals began banding together to raise money for the preservation of the land, as its natural beauty was being destroyed by the cut-and-run-style clearcutting employed by the timber companies.

[159][160] Knoxville Mayor Ben Morton, travel writer Horace Kephart, explorer Paul M. Fink, and photographers Jim Thompson and George Masa were also instrumental in fostering the development of the park.

[163] That same year, a lodge was established atop Mount Le Conte by hiker Paul Adams to entertain visiting dignitaries from Washington, D.C.[164] President Calvin Coolidge signed legislation on May 22, 1926, which authorized the park, but there was no nucleus of federally owned land around which to develop it.

[160] Along with convincing logging firms to sell lucrative lumber rights, the park commissions had to negotiate the purchase of thousands of small farms and remove entire communities.

During the Great Depression, the Civilian Conservation Corps, the Works Progress Administration, and other federal organizations hired workers to build trails, firetowers, roads, and other infrastructure in the park.

On September 2, 1940, President Franklin D. Roosevelt formally dedicated the park in a ceremony at the Rockefeller Memorial at Newfound Gap to a crowd of approximately 10,000 people.

The celebrity status of country music singer and actress Dolly Parton, who grew up in nearby Pittman Center, Tennessee, brought further attention to the park in the latter 20th and 21st centuries.