Geography of Tennessee
The U.S. state of Tennessee is geographically diverse, with varying terrains and several distinct physiographic regions. Its landforms range from the Blue Ridge Mountains in the eastern part of the state to flat and fertile plains along the Mississippi River. The state is geographically, legally, culturally, and economically divided into three Grand Divisions: East Tennessee, Middle Tennessee, and West Tennessee.
Borders[edit]
Tennessee's eastern boundary roughly follows the highest crests of the Blue Ridge Mountains, and the Mississippi River forms its western boundary.[3] Due to flooding of the Mississippi River that has changed its path, the state's western boundary deviates from the river in some places.[4] Neither the northern nor the southern border of Tennessee follows a geographic feature. The northern border was originally defined as the parallel 36°30′ north and the Royal Colonial Boundary of 1665, but due to faulty surveys, the border begins north of this line in the east, and to the west, gradually veers north with multiple minute shifts.[3] Once at the Tennessee River in the western part of the state, the border shifts south onto the actual 36°30′ parallel.[5] An 1818 survey erroneously placed the state's southern border 1 mile (1.6 km) south of the 35th parallel; Georgia legislators continue to dispute this placement, as it prevents Georgia from accessing the Tennessee River.[6]
Hydrology[edit]
The state is drained by three major rivers, the Tennessee, Cumberland, and Mississippi. The Tennessee River begins at the juncture of the Holston and French Broad rivers in Knoxville, flows southwest to Chattanooga, and exits into Alabama before reemerging in the western part of the state and flowing north into Kentucky.[38] Major tributaries of the Tennessee River include the Clinch, Little Tennessee, Hiwassee, Sequatchie, Elk, Beech, Buffalo, Duck, and Big Sandy rivers.[38] The Cumberland River flows through the north-central part of the state, emerging in the northeastern Highland Rim, passing through Nashville and the northern part of the Nashville Basin before turning northwest to Clarksville and entering Kentucky west of the Tennessee River.[39] Its principal branches in Tennessee are the Obey, Caney Fork, Stones, Harpeth, and Red rivers.[39] The Mississippi River forms the state's western boundary, where Memphis lies.[40] Its tributaries are the Obion, Forked Deer, Hatchie, Loosahatchie, and Wolf rivers.[40] The Tennessee Valley Authority (TVA) and U.S. Army Corps of Engineers operate many hydroelectric dams on the Tennessee and Cumberland rivers and their tributaries. These dams form many large reservoirs throughout the state.[41]
About half the state's land area is in the Tennessee Valley drainage basin of the Tennessee River.[38] The Cumberland River basin covers the northern half of Middle Tennessee and a small portion of East Tennessee.[39] A small part of north-central Tennessee in Sumner, Macon, and Clay Counties is in the Green River watershed.[42] All three of these basins are tributaries of the Ohio River watershed. Most of West Tennessee is in the Lower Mississippi River watershed.[40] The entirety of the state is in the Mississippi River watershed, except for a small sliver in Bradley and Polk Counties traversed by the Conasauga River, which is part of the Mobile Bay watershed.[43]