Interstate 40 in Tennessee
Interstate 40 is part of the Interstate Highway System that runs from Barstow, California, to Wilmington, North Carolina. The highway crosses the state of Tennessee from west to east, from the Mississippi River at the Arkansas state line to the Blue Ridge Mountains at the North Carolina state line. At, the Tennessee segment of I-40 is the longest of the eight states through which it passes and the state's longest Interstate Highway.
I-40 passes through Tennessee's three largest cities—Memphis, Nashville, and Knoxville—and serves the Great Smoky Mountains National Park, the most-visited national park in the United States. It crosses all of Tennessee's physiographic regions and Grand Divisions—the Mississippi embayment and Gulf Coastal Plain in West Tennessee, the Highland Rim and Nashville Basin in Middle Tennessee, and the Cumberland Plateau, Cumberland Mountains, Ridge-and-Valley Appalachians, and Blue Ridge Mountains in East Tennessee. Landscapes on the route vary from flat, level plains and swamplands in the west to irregular rolling hills, cavernous limestone bluffs, and deep river gorges in the central part of the state, to plateau tablelands, broad river valleys, narrow mountain passes, and mountain peaks in the east.
The Interstate parallels the older U.S. Route 70 corridor for its entire length in the state. It has interchanges and concurrencies with four other mainline Interstate Highways, and has five auxiliary routes: I-140, I-240, I-440, I-640, and I-840. I-40 in Tennessee was mostly complete by the late 1960s, having been constructed in segments. The stretch between Memphis and Nashville, completed in 1966, was the state's first major Interstate segment to be finished. The last planned section was completed in 1975, and much of the route has been widened and reconstructed since then.
The I-40 corridor between Memphis and Nashville is known as Music Highway because it passes through a region which was instrumental in the development of American popular music. In Memphis, the highway is also nationally significant due to a 1971 U.S. Supreme Court case which established the modern process of judicial review of infrastructure projects. Community opposition to the highway's proposed routing through Overton Park led to a nearly-25-year activist campaign which culminated in the case. This resulted in the state abandoning the highway's original alignment and relocating it onto what was originally a section of I-240.
Route description
I-40 runs for through Tennessee, making it the second-longest stretch of Interstate Highway within a single state east of the Mississippi River. It is the only Interstate Highway to pass through all three of the state's Grand Divisions and all nine physiographic regions. The highway is maintained by the Tennessee Department of Transportation. The busiest stretch of highway in Tennessee is on the segment concurrent with I-75 in Knoxville between a connector to US 11/70 and Papermill Road, which had an average daily traffic volume of 218,583 vehicles in 2022. The lowest daily traffic volume that year was 26,985 vehicles at the North Carolina state line. The busiest weigh station in the country is on I-40/I-75 in Farragut, a suburb of Knoxville, which serves more than 2.4 million trucks annually.West Tennessee
Memphis
I-40 enters Tennessee from Arkansas in a direct east–west alignment via the six-lane Hernando de Soto Bridge, a tied-arch bridge which spans the Mississippi River and has a total length of about. Entering the city of Memphis, the Interstate crosses the southern half of Mud Island before crossing the Wolf River Harbor and Mississippi Alluvial Plain into Downtown Memphis, where the bridge ends next to the Memphis Pyramid. The highway then intersects US 51 and, just beyond this point, abruptly turns 90 degrees north near Midtown at an interchange with the western terminus of I-240, a southern bypass route around the central city. It then intersects SR 14. Proceeding north, the highway crosses the Wolf River and reaches the eastern terminus of SR 300, a controlled-access connector to US 51. The Interstate then shifts due east, bypassing central Memphis to the north. Passing near the neighborhoods of Frayser and Raleigh, I-40 intersects a number of surface streets and crosses the Wolf River for a second time about later. It then meets SR 14 again and turns southeast.A few miles later, I-40 reaches a complex four-level stack interchange with US 64/70/79 and the eastern ends of I-240 and Sam Cooper Boulevard; a pair of overpasses carries its traffic northeast. Entering a straightaway, the Interstate crosses the Wolf River for a third time; over the next several miles, it passes through the suburban neighborhoods of East Memphis and Cordova and the incorporated suburb of Bartlett in eastern Shelby County. This stretch has eight lanes; the left lanes serve as high-occupancy vehicle lanes during rush hour, and it has several interchanges with local thoroughfares. The highway then intersects US 64 and narrows to four lanes. After passing through Lakeland, the Interstate reaches a cloverleaf interchange with the eastern ends of I-269 and SR 385 near the suburb of Arlington.
Gulf coastal plain
Leaving the Memphis area, I-40 enters Fayette County east of Arlington; about later, it crosses the Loosahatchie River and adjacent wetlands. Over the next, the Interstate crosses a level expanse of farmland and some woodlands and swamplands in a straight alignment, bypassing most cities and communities. An interchange with SR 59 is at exit 35, which provides access to Covington and Somerville. The highway enters Haywood County near the site of Ford Motor Company's Blue Oval City manufacturing facility. Beyond this point, it turns north and enters Hatchie National Wildlife Refuge; the highway crosses the Hatchie River and a number of streams and swamps in a long straightaway. I-40 turns east after the refuge and passes southeast of Brownsville, where it intersects SR 76, SR 19, and US 70. The highway then enters Madison County.Crossing a mix of level farmland and swamplands, I-40 enters Jackson beyond this point and crosses the South Fork of the Forked Deer River. Passing through northern Jackson, the Interstate widens to six lanes and has six urban interchanges. In quick succession, the highway intersects US 412, which connects to Alamo and Dyersburg; the US 45 Bypass ; and US 45, which also provides access to Humboldt and Milan. The Interstate passes through a residential area and reaches US 70, which connects to Huntingdon. I-40 then shrinks back to four lanes.
The highway continues east-northeast through farmland and woodlands with low, rolling hills. After entering Henderson County, I-40 crosses the Middle Fork of the Forked Deer River. It intersects SR 22, a major north–south corridor in West Tennessee which accesses Lexington and Huntington, near the town of Parkers Crossroads. The Interstate then crosses the Big Sandy River before proceeding through the northern half of Natchez Trace State Park. Over the next few miles, the highway transitions several times between Henderson and Carroll counties before entering Decatur County. It reaches US 641/SR 69, another major north–south corridor connecting Camden and Decaturville, at the Decatur–Benton county line. About later, the Interstate descends about on a steep grade over into the Western Valley of the Tennessee River; the westbound lanes have a truck-climbing lane. Entering Tennessee National Wildlife Refuge at the bottom of the grade, I-40 crosses Kentucky Lake, a Tennessee River reservoir, on the Jimmy Mann Evans Memorial Bridge into Middle Tennessee.
Middle Tennessee
Western Highland Rim
Crossing the Tennessee River into Humphreys County, I-40 exits the refuge after a few miles and traverses vast woodlands in the rugged hills of the Western Highland Rim. This section is characterized by several ascents and descents, with the route roughly following a crooked stream valley. About beyond the river, the highway crosses the Buffalo River and intersects SR 13, which connects to Linden and Waverly. It then descends another steep grade, again with a westbound truck-climbing lane, and crosses into Hickman County. It soon reaches SR 50, which connects to Centerville, and crosses the Duck River. The highway enters Dickson County several miles later, where it reaches SR 48 and access to Centerville and Dickson. I-40 then crosses the Piney River.Several miles beyond this point is an interchange with SR 46, the primary exit for Dickson, which also provides access to Centerville and Columbia. Near the town of Burns, I-40 reaches the western terminus of I-840, the outer southern beltway around Nashville. The highway continues through woodlands and rugged terrain and, crossing into Williamson County, ascends steeply for a short distance with an eastbound truck-climbing lane. Along this ascent is an interchange with SR 96, which connects to the Nashville suburbs of Fairview and Franklin. The Interstate enters Cheatham County a few miles later, and gradually descends into the Nashville Basin. It then passes the towns of Kingston Springs and Pegram, and crosses the Harpeth River twice in quick succession.
Nashville
Around milepost 191, I-40 enters Davidson County and crosses the Harpeth River for the third time a few miles later. Entering the urbanized parts of the Nashville metropolitan area, the Interstate widens to six lanes near Bellevue. The highway enters the outskirts of Nashville, the state capital and Tennessee's largest city, and intersects US 70S near a bend in the Cumberland River. It then reaches Old Hickory Boulevard and intersects US 70 a few miles later. I-40 then widens to eight lanes, and has a four-level interchange with SR 155 which includes the western terminus of a northern controlled-access beltway around Nashville. South of Tennessee State University is the western terminus of I-440, the southern loop around central Nashville, where I-40 goes down to six lanes.The highway briefly passes through the Jefferson Street neighborhood before entering downtown Nashville near Fisk University, where it begins a brief concurrency with I-65 and turns southeast. As part of the Inner Loop encircling downtown Nashville, the two concurrent Interstates have interchanges in quick succession with US 70, US 70S/431, Church Street, and Demonbreun Street. Next they shift east-northeast near Music Row and the neighborhoods of The Gulch and SoBro, where I-65 turns south toward Huntsville, Alabama. Briefly independent for about, I-40 crosses a viaduct and intersects US 31A/US 41A before beginning a brief concurrency with I-24. The concurrent Interstates turn southeast, expanding back to eight lanes. I-24 then turns southeast towards Chattanooga, and I-40 shifts eastward. The eastern terminus of I-440 and a connector road to US 41/70S are accessible from the westbound lanes of I-40 at this interchange.
Entering the Donelson neighborhood, I-40 intersects SR 155 near Nashville International Airport. Beginning here, the left lanes are HOV lanes during rush hour. A partial exit accesses an airport connector road; immediately beyond is a second airport access road at SR 255. Shifting northeast, I-40 crosses the Stones River near J. Percy Priest Dam. Entering the southern fringes of the Hermitage neighborhood, the highway meets Old Hickory Boulevard again at an interchange with SR 45 and once again shifts eastward into a straightaway. I-40 enters Wilson County and then has an interchange with SR 171 in the suburb of Mount Juliet. Entering another long straightaway, the highway intersects SR 109 after some distance, which provides access to Gallatin to the north. A few miles later, it has a trumpet interchange with the eastern terminus of I-840 east of Lebanon. I-40 then enters Lebanon, shrinking back to four lanes, and interchanges with US 231 and US 70.