Interstate 75 (I-75) in the US state of Tennessee runs from Chattanooga to Jellico by way of Knoxville. I-75 enters the East Tennessee region from Georgia, following the Tennessee Valley all the way through Knoxville to near Rocky Top, then climbs into the Cumberland Mountains before crossing over into Kentucky at Jellico.
Of the six states that I-75 traverses, the segment in Tennessee is the shortest, at . Between Chattanooga and Knoxville, I-75 follows the route of U.S. Route 11 (US 11), and, from Knoxville into Kentucky, it follows the route of US 25W. Beginning in Chattanooga, I-75 follows the route of US 41 for the rest of the length to its southern terminus in Miami, Florida.
Route description Chattanooga
I-75 enters Tennessee on the eastern side of East Ridge, a southern suburb of Chattanooga. Less than into Tennessee is an interchange with US 41 (unsigned US 76). About later, at exit 2, is a three-way interchange with the eastern terminus of I-24, which runs west into downtown Chattanooga, then to northwest towards Nashville while connecting to the northern terminus of I-59 near Wildwood, Georgia that goes southwest toward Birmingham, Alabama. At this interchange, I-75 turns northeast, running along the eastern boundary of Chattanooga. Almost later is an interchange with State Route 320 (SR 320), which connects to East Brainerd, and, about a half mile () later is a three-way interchange with the southern terminus of SR 153, a controlled-access highway that runs northwest to the Chattanooga Metropolitan Airport and crosses the Tennessee River on the Chickamauga Dam. Accessible from the northbound lanes at this interchange is Hamilton Place Boulevard, a connector to Hamilton Place. The southbound lanes of I-75 are also accessible from an entrance ramp from this road. At this point, I-75 enters a large commercial area dominated by Hamilton Place and has an interchange with Shallowford Road about later. A few miles later, at exit 7, I-75 has an interchange with US 11 southbound, US 64 westbound, and SR 317 westbound and begins a concurrency with these respective routes. Turning slightly northeast, the Interstate crosses a Norfolk Southern Railway, and, at exit 9, SR 317 splits off to the east. I-75 then crosses a steep ridge, passing between the Enterprise South Industrial Park to the west and Collegedale to the east. A few miles later, in Ooltewah, US 11/US 64 split off at exit 11, where the route narrows to six lanes. I-75 then turns northwest and narrows to four lanes.
Bradley to Loudon counties
A few miles later, I-75 begins a steep ascent up the western slope of White Oak Mountain, where the northbound lanes receive a truck climbing lane. At this point, the Interstate turns northeast and, for the next , traverses east northeast over the top of White Oak Mountain, where it crosses into Bradley County. I-75 then runs for the next several miles through a predominantly wooded and agricultural area and crossing a few ridges before reaching Cleveland at an interchange with APD-40 eastbound (US 64 Bypass [US 64 Byp.]), a bypass and connector to US 64. Running along the western edge of Cleveland, I-75 has an interchange with SR 60 about later, also crossing Candies Creek Ridge at this location, and, less than later, an interchange with Paul Huff Parkway, a major thoroughfare along the northern part of Cleveland. The Interstate then leaves Cleveland and enters rural northern Bradley County, running northeast. Beginning at this point and continuing for nearly , I-75 is very straight and flat, with few curves. Nearly the entirety of this section also contains an extremely wide median, mostly separated by trees. In some locations, the north and southbound lanes are as much as a half mile () apart.
About north of the central business district of Cleveland, I-75 curves to the northeast, crosses the Hiwassee River into McMinn County, and then curves back to the northwest. This area is extremely susceptible to fog hazards, which obscures the visibility of drivers, and several bad accidents have occurred on this section as a result. Running through mostly wooded and agricultural areas, I-75 reaches Athens about later and has an interchange with SR 30, a major east–west corridor in East Tennessee. Running through northern McMinn County, the Interstate passes near several unincorporated communities and has interchanges with several secondary state highways. Around milemarker 58, I-75 enters Monroe County and, a few miles later, passes near the town of Sweetwater, containing an interchange with SR 68, another major primary state highway. A few miles later, I-75 crosses into Loudon County. At exit 72 is an interchange with SR 72, which connects to Loudon, and, a few miles later, the highway crosses the Tennessee River on the Mitchell W. Stout Memorial Bridges. I-75 then enters a predominantly commercial and residential area and has an interchange with US 321 and SR 95 in Lenoir City. These routes also connect to Oak Ridge and Maryville. Curving slightly to the west and then again to the east, I-75 reaches an interchange with I-40 westbound about later, where it begins a concurrency with I-40, and the combined routes widen to six lanes. Less than later, about west southwest of Knoxville, the concurrent routes cross into Knox County.
Knoxville
Running approximately east-northeast, the two Interstates pass through the western suburbs of Knoxville, including Farragut and West Knoxville. Along this concurrency, exits are numbered according to I-40 mileage. At exit 374 is an interchange with SR 131 (Lovell Road), where the highway widens to eight lanes, and, less than later is a four-way interchange with the Pellissippi Parkway (SR 162 westbound, I-140 eastbound), which connects to Oak Ridge to the west and Maryville to the east. At exit 380 is an interchange with US 11/US 70 (Kingston Pike), which connects to the West Hills neighborhood and West Town Mall. This section is the most heavily traveled section of highway in Tennessee, with an annual average daily traffic (AADT) volume of more than 210,000 vehicles. About later, at an interchange with the western terminus of I-640, the northern bypass around Downtown Knoxville, I-75 splits north off of I-40 and onto a concurrency with I-640. Along this concurrency, exits are numbered according to I-640 mileage. Heading north, the Interstates come to an interchange with SR 62 (Western Avenue) about later. About later is a complicated interchange with I-275 southbound, the former route of I-75, and US 25W, where I-75 splits off and turns northwest.
Clinch River Valley and Cumberland Mountains Leaving Knoxville, I-75 runs north northwest, crossing several paralleling ridges of the Ridge-and-Valley Appalachians. The terrain for the next of I-75 north of Knoxville is characterized mostly by a slight downhill grade. At exit 112 in Powell, I-75 once again has an interchange with SR 131, and the Interstate narrows from six to four lanes. Entering a rural area, I-75 runs along a creek valley for the next several miles that bisects several ridges in a crooked and hazardous segment marked by several S-curves. Maintaining its north-northwesterly direction, I-75 crosses into Anderson County. Beyond this section, the Cumberland Mountains become visible in the distance. At exit 122, the Interstate has an interchange with SR 61 near Clinton. I-75 then descends sharply into a valley, crossing the Clinch River a few miles later. About later, near the community of Rocky Top, I-75 has interchanges with US 441 and US 25W, beginning a concurrency with the latter. The Interstate then crosses into Campbell County.
For approximately the last in Tennessee, I-75 traverses the rugged terrain of the Cumberland Mountains. Although this stretch of highway is considered to be scenic, it is one of the most hazardous stretches, which is characterized by steep ascents (northbound) and steep downhill grades (southbound). About north of Rocky Top, I-75 begins the first of three major ascents for a few miles before leveling out, and. When the highway approaches the community of Caryville, US 25W splits off and I-75 runs concurrently with SR 63. The Interstate then begins a second ascent, which is steeper than the first ascent, adding a truck climbing lane going northbound. About later, the highway levels out onto a plateau and the truck lane terminates. Less than later, SR 63 departs near the unincorporated community of Pioneer. Traveling through a further sparsely populated rural area marked by dense woodlands, I-75 remains relatively flat for the next few miles before beginning its final major ascent, this time ascending Jellico Mountain, which in turn is part of the Pine Mountain subrange, and adding a truck climbing lane for the final time. I-75 curves sharply to the northeast, and, about later, it reaches the peak of Jellico Mountain, where the truck lane ends for the final time. I-75 traverses the peak of Jellico Mountain for approximately the next on a segment marked by rolling hills, and reaches its highest elevation along its entire route, at more than . The Interstate then begins a steep descent off of the mountain, beginning a transition into the Cumberland Plateau region. About later, it levels out and enters the city of Jellico where it has an interchange with US 25W. For the next mile () or so, it has a slight uphill grade before entering the hilly terrain of the Cumberland Plateau in Kentucky.
History Early history
The first two segments that became I-75 in Tennessee were located in Knoxville and Chattanooga, and were constructed prior to the passage of the Federal-Aid Highway Act of 1956. The segment in Knoxville, which was concurrent with I-40, was approximately of a freeway downtown, completed in two phases on November 14, 1952, and December 10, 1955, that was initially known as the Magnolia Avenue Expressway. The segment of this route that became I-75 was located between Unaka Street and a cloverleaf interchange that became the split between I-75 (now I-275) and I-40. The segment in Chattanooga was an approximately relocated segment of US 11 and US 64 between approximately north of the present interchange with those routes and SR 317 (Bonny Oaks Drive, then SR 2A) and the interchange with US 11/US 64 (Lee Highway) in Ooltewah. This route, which was initially known as the Summit Bypass, opened to traffic on July 23, 1954, and was constructed as a bypass around a one-lane railroad tunnel in Collegedale that had been the site of many traffic accidents.