Tennessee’s landforms fall into six main physiographic regions that line up from east to west: the Blue Ridge Mountains, the Ridge-and-Valley Appalachians, the Cumberland Plateau, the Highland Rim, the Nashville Basin and the Gulf Coastal Plain, which ends in the Mississippi Alluvial Plain. The highest point is Kuwohi, formerly Clingmans Dome, at 2,025 m (6,643 ft) in the Great Smoky Mountains; the lowest is 54 m (178 ft) on the Mississippi River at the Mississippi state line in Memphis. The state covers about 109,150 km² (42,143 sq mi) and stretches about 710 km (440 mi) east to west but only 180 km (112 mi) north to south, Interstate 40 runs 732 km (455 mi) across the state from Memphis through Nashville to Knoxville, and along the way the rocks generally get younger from east to west.
The Blue Ridge: Kuwohi and the Great Smoky Mountains
The eastern border with North Carolina roughly follows the highest crests of the Blue Ridge, which in Tennessee is split into several subranges: the Great Smoky Mountains, the Bald Mountains, the Unicoi Mountains, the Unaka Mountains and the Iron Mountains. Their average elevation is about 1,500 m (5,000 ft). These are the state’s oldest rocks, Precambrian granite and igneous strata more than a billion years old, along with Cambrian sediments altered by metamorphism.
Kuwohi rises to 2,025 m (6,643 ft) on the state line inside Great Smoky Mountains National Park. It is the highest point in Tennessee, the highest point on the 3,528 km (2,192 mi) Appalachian Trail, and the third-highest summit in eastern mainland North America, after Mount Mitchell and Mount Craig in North Carolina. The geographer Arnold Guyot named it Clingmans Dome in 1859 after Thomas Clingman, who had measured it the year before. After an application backed by the Eastern Band of Cherokee Indians, the US Board on Geographic Names restored the Cherokee name, Kuwohi, on September 18, 2024. The mountain lies entirely within the Tennessee River watershed; Little River rises on its north slope. The Blue Ridge was never more than thinly settled, and most of it is now protected in the national park, the Cherokee National Forest and several wilderness areas. Our Great Smoky Mountains park guide covers its trails, balds and waterfalls.
The Great Valley of East Tennessee, Bristol to Chattanooga
West of the Blue Ridge, for about 89 km (55 mi), the land becomes a washboard of long, parallel ridges and valleys running northeast to southwest, the same direction as the whole Appalachian chain. This is the Ridge-and-Valley province, also called the Tennessee Valley or the Great Valley of East Tennessee, largely coterminous with the Great Appalachian Valley. Most of the ridges are low, though the higher ones are locally called mountains, and the valleys between them are broad enough for farms, roads and cities. The rocks are Paleozoic shales and carbonates, many of them Ordovician.
Three of the state’s urban areas lie in this valley: the Tri-Cities of Bristol, Johnson City and Kingsport in the northeast, Knoxville in the middle, and Chattanooga at the southern end. At Knoxville the Holston and French Broad rivers meet to form the Tennessee River, which follows the valley southwest through Chattanooga and misses Georgia by only about 76 m (250 ft) before crossing into Alabama. The river’s 1,049 km (652 mi) journey, which later brings it back north through Tennessee, is followed in our Tennessee River geography guide.
The Cumberland Plateau’s Escarpments and Fall Creek Falls
West of the valley the land rises abruptly onto the Cumberland Plateau, part of the larger Appalachian Plateau. Its tablelands stand between about 460 and 760 m (1,500 and 2,500 ft), averaging roughly 610 m (2,000 ft), and the eastern side is higher than the western. The plateau was formed of Pennsylvanian sandstone, siltstone and shale laid down about 300 million years ago, with abundant coal. In the northeast the Cumberland Mountains top 1,100 m (3,500 ft), while in the south the plateau is split lengthwise by the Sequatchie Valley, a long straight trough probably formed by erosion of a compressed anticline. On the Georgia line, Lookout Mountain rises above Chattanooga; the Battle of Lookout Mountain was fought on its slopes on November 24, 1863.
The eastern edge of the plateau is a fairly clean escarpment, but the western edge is ragged, cut by long, crooked stream valleys lined with cliffs and waterfalls. Fall Creek Falls State Park, in Van Buren and Bledsoe counties, protects the upper gorge of Cane Creek, where the water drops several hundred feet in less than a mile. Its namesake, Fall Creek Falls, plunges 78 m (256 ft), the highest free-fall waterfall east of the Mississippi River. Nearby, Cane Creek Falls drops 26 m and Rockhouse Creek 38 m. The plateau is also a human boundary: the line between East and Middle Tennessee runs along its top, as does the line between Eastern and Central Time.
The Highland Rim, Tennessee’s Largest Region
Below the plateau’s western escarpment lies the Highland Rim, an elevated plain that wraps in a ring around the Nashville Basin. It is Tennessee’s largest physiographic region and belongs, with the basin, to the Interior Low Plateaus. Geographers split it into two halves. The Eastern Highland Rim is mostly level with scattered rolling hills at around 300 m (1,000 ft). The Western Highland Rim is more broken, a country of rounded knobs, steep ravines and meandering streams that descends from about 270 m (900 ft) on its eastern side to 210 m (700 ft) at its western escarpment. Clarksville, the state’s fifth-largest city, sits on the northwestern Rim.
The Rim was laid down in the Mississippian period on soluble limestone, and that rock explains one of Tennessee’s records. Water dissolving the limestone has created sinkholes, sinking streams and caves, and Tennessee has more caves than any other US state, more than 10,000 documented.
The Nashville Basin, a Dome Worn Hollow
In the middle of the Rim, the land drops into the Nashville Basin, also called the Central Basin. It averages about 180 m (600 ft), though some hills inside it stand higher than the Eastern Rim around it. The basin’s shape is a geological irony: its inner part is a dome, uplifted between 300 and 400 million years ago, that erosion has since worn down into a lowland floored with Ordovician shale and limestone, so the low ground sits where the high ground used to be.
That limestone lies close to the surface, so the basin is karst country with caves, sinkholes and underground streams, but it also weathers into rich soil, and the level floor became some of the best farmland in the state. Nashville grew in the northwestern corner of the basin on the Cumberland River, and its suburbs spread south, southeast and east across the flat ground rather than climbing the Rim. Murfreesboro, near the basin’s centre, is the geographic centre of Tennessee.
The Western Tennessee Valley and the Gulf Coastal Plain
West of the Rim is a narrow strip, about 16 km (10 mi) wide, of hilly land along the Tennessee River as it flows back north towards Kentucky. Most geographers do not count this Western Tennessee Valley as a major province, but the river is the boundary between Middle and West Tennessee. Some maps put the strip’s western half in the Gulf Coastal Plain, which geographers treat as inaccurate because it drains to the Tennessee rather than directly to the Mississippi. Devonian and Silurian rocks, 360 to 420 million years old, surface here.
Beyond it lies the Gulf Coastal Plain, part of a broad plain that begins at the Gulf of Mexico and extends north into southern Illinois. In Tennessee it has two sections. The eastern part, the West Tennessee Highlands or Uplands, is low rolling hills and wide stream valleys on Cretaceous sediments. Westward the land flattens onto younger Tertiary deposits blanketed with thick, fertile loess, windblown silt, and this flat western plain is one of the most productive cotton regions in the country. The plain ends abruptly at the Chickasaw Bluffs, four bluffs rising about 15 to 60 m (50 to 200 ft) above the river floodplain between Fulton and Memphis. The Chickasaw people who gave them their name used them to control traffic on the river in the 18th century, and Memphis was built on the southernmost bluff, safe above the floods.
Reelfoot Lake and the Mississippi Bottoms
Below the bluffs is the westernmost region, a strip of the Mississippi Alluvial Plain known as the Mississippi Bottoms. It is 16 to 23 km (10 to 14 mi) wide, lies below 91 m (300 ft), and is made of lowlands, floodplains and swamps built from the youngest sediments in the state. The Mississippi forms the state’s western border with Arkansas and Missouri, and the river valleys that drain into it hold the state’s youngest deposits, sands and silts laid down in the last 2.6 million years.
The region’s most remarkable landform was made in a single winter. During the New Madrid earthquakes of December 1811 to February 1812, centred near New Madrid, Missouri, the ground in northwest Tennessee subsided, and water filled the hollow to create Reelfoot Lake in Lake and Obion counties. The old Reelfoot River, which had flowed into the Mississippi, disappeared. Today the lake is shallow and swamp-like, a network of open basins, the largest called Blue Basin, linked by bayou-like channels among bald cypress trees.
Levees built from 1917 to 1920 hold its water level, the state later acquired the land and lake, Reelfoot Lake State Park now protects it, and the National Park Service named it a national natural landmark in 1966; it is known for nesting bald eagles. At the southern end of the Bottoms the state reaches its lowest ground, 54 m above sea level on the river at Memphis, about 1,970 m below the summit of Kuwohi. To follow that river beyond the state line, see our Mississippi River geography guide, which traces the channel that drew Tennessee’s western edge.