Great Smoky Mountains National Park encompasses over 800 square miles (521,490 acres) divided almost equally between the states of North Carolina and Tennessee, and is one of the largest protected areas in the eastern United States. The uninterrupted chain of mountains range to 6,643 feet and for 36 miles the crest of the range remains more than 5,000 feet above sea level, including 16 peaks over 6,000 feet. Precipitation levels are among the highest on the North American continent, with annual averages of 85 inches in parts of the park. Higher elevations average 69 inches of snow annually. The Park is within easy driving distance of two-thirds of the U.S. population and is the most heavily visited National Park, with nearly 10 million annual visitors. The extraordinary biodiversity of the Great Smokies is world-renowned, as reflected in its designation as an International Biosphere Reserve. Every major eastern forest type can be found within the Park's boundaries. The park's 1,637 vascular plant species include over 130 species of trees, and 60-70 distinct vegetative communities. At lower elevations, forest of Tulip Poplar dominate large areas that historically were farmed. In sheltered rich coves (typically with northerly aspects), yellow buckeye, sugar maple, white basswood, and tulip poplar dominate the overstory. In coves with steeper v-shaped drainages, silverbell and hemlock dominate the canopy and rhododendron often forms a thick, impenetrable understory. Drier slopes (south and west facing) are dominated by Chestnut Oak with a mountain laurel understory. Dry ridges typically have a large component of pine (pitch, shortleaf, Virginia, and Table Mountain), and dry site oaks (chestnut, scarlet, and black). At higher elevations, the northern hardwood forest is prevalent, which is composed of sugar maple, yellow buckeye, yellow birch, and American beech. At the highest elevations, red spruce forests (above 5,200 feet), and red spruce-Fraser fir forests (above 6,000 feet) dominate. Scattered throughout the Park are unique communities such as grassy balds, heath balds, beech gaps, caves, vernal pools, and small wetlands, which are significant because they support unique biota, are generally small in aerial extent, and have a limited distribution in the southern Appalachians. The park supports 14 federally-listed Endangered or Threatened species, 25 animal species that are under consideration for federal listing as Endangered or Threatened, and 194 species of plants and animals ranked as globally vulnerable, imperiled, or critically imperiled by The Nature Conservancy. There are 405 plant species that occur in fewer than five locations in the park, 3 of these are federally-listed, and 74 are state-listed as threatened or endangered. Great Smoky Mountains contains approximately 75 percent of all the Fraser fir forest that remains in existence, a significant proportion of all remaining Southern Appalachian northern hardwood forest, and the largest contiguous tracts of old-growth (all types) remaining in the eastern U.S. The Great Smoky Mountains National Park was designated a International Biosphere Reserve in 1976 and a World Heritage Site on December 6, 1983. Over 245,000 acres of land in Tennessee is open to hiking, road biking, birding, camping, and other forms of recreation. The variety of elevations and habitats leads to an incredible diversity of wildlife. Over 800 miles of hiking trails are available, including over 70 miles of the Appalachian Trail. Cades Cove and Clingman's Dome are popular tourist attractions and worth visiting. Clingman's Dome is the highest point in Tennessee and second highest in the eastern United States at 6643 feet.
The park supports 230 species of birds of which 110 species breed. Two hundred species have been documented in recent years, including one of the highest diversities of breeding neotropical migratory birds of any area in the United States. In some habitats, over 80 percent of the breeding bird community is made up of neotropical migrants (Simons and Shriner 1998). Thirty-three species previously documented here are considered extirpated, extinct, or vagrant. Part of the reason for such diversity of neotropical migrants may be due to the invertebrate diversity. This is still being studied, but numbers in well-known groups are already impressive, including 1,500 species of beetles and 1,000 species of lepidopterans. Game species are commonly observed, including deer and wild turkey. Migratory songbirds abound in the expanses of mature forest across the National Park. Nesting magnolia warbler, black-throated blue warbler, and Blackburnian warblers are highlights. Black bear may be seen as there is a thriving population in the east Tennessee mountains.
Uncommon birds in Tennessee that breed in the Park include black-capped chickadee, common raven, northern saw-whet owl, and yellow-bellied sapsucker.
From Tennessee and south of I-40, accessible from several locations, however usually accessed via US 321 from Maryville and US 441 from Gatlingburg.