I-24 runs diagonally from
I-57 south of
Marion, Illinois, to
I-75 at
Chattanooga, Tennessee. In Kentucky, the road passes through
Paducah and
Eddyville. Its length in Tennessee is longer than the other three states combined. There are two segments that are separated by the segment in Georgia. Through Georgia, it carries the
unsigned State Route 409 (SR 409) designation for internal
Georgia Department of Transportation (GDOT) purposes.
Illinois I-24 begins at exit 44 on
I-57 in southern
Williamson County, near the community of
Pulleys Mill. The highway heads southeast into rural
Johnson County, bypassing
Goreville to the east. It reaches an exit at Tunnel Hill Road, which serves Goreville and
Tunnel Hill. The highway continues south to its next exit at
US Route 45 (US 45) north of
Vienna. It reaches its next exit at
Illinois Route 146 (IL 146) in eastern Vienna. I-24 heads southeast from Vienna into
Massac County. Its first exit in Massac County is at Big Bay Road, which serves the communities of
Big Bay and
New Columbia. I-24 continues southward, bypassing the community of
Round Knob before entering
Metropolis. The highway meets US 45 again in Metropolis and passes west of
Fort Massac State Park. It leaves Metropolis and crosses the
I-24 Bridge over the
Ohio River. After that, it continues into Kentucky.
Kentucky , the only historic house used as a
rest area in the US I-24 enters the
Jackson Purchase region of western Kentucky on a north–south alignment. Immediately within
McCracken County, the route begins gradually veering southeast and enters the western fringes of
Paducah a few miles later. The welcome center in Paducah utilizes
Whitehaven, the only historic house in the United States used as a
rest area. In Paducah, the Interstate continues to shift southeast and has interchanges with
US 60,
US 62, and
US 45. Passing through the
Hendron and
Farley communities adjacent to Paducah, the highway shifts into a direct east–west alignment several miles later and has an interchange with
US 68 in
Reidland. The route then enters
Marshall County and, about later, reaches an interchange with
I-69 and a connector road to US 62 and
Calvert City to the north. Here, it begins a
concurrency with the former. The two Interstates then shift northeast and have an interchange with US 62 about later. A short distance later, the Interstates cross the
Tennessee River onto the
Pennyroyal Plateau and
Livingston County just north of
Kentucky Dam and its
Kentucky Lake impoundment. The highways then have an interchange with
Kentucky Route 453 (KY 453) north of
Lake City and
Land Between the Lakes National Recreation Area. They then cross the
Cumberland River about later into
Lyon County a few miles north of
Barkley Dam and
Lake Barkley. Gradually veering eastward, the two Interstates reach US 62 again near
Kuttawa and
Eddyville. Less than later, I-69 splits off to the northeast at a
trumpet interchange, and I-24 passes through
Mineral Mound State Park, veering southeast a few miles later. Passing through a mostly wooded area, the Interstate crosses
KY 93 without an interchange, and then has an interchange with
KY 293 near the
Kentucky State Penitentiary. It then crosses an inlet of Lake Barkley a few miles later. Some distance later, the freeway enters a landscape consisting mostly of farmland and dips briefly into the southern tip of
Caldwell County, where it has an interchange with
KY 139. The Interstate then enters
Trigg County and crosses the Muddy Fork Little River a short distance later. About later, the Interstate has an interchange with US 68 and
KY 80 between
Cadiz and
Hopkinsville. The highway then crosses into
Christian County a few miles later. Passing over the next several miles through additional farmland and bypassing Hopkinsville to the southwest, the Interstate reaches the southern terminus of
I-169 at a trumpet interchange. About later, the Interstate has a
partial cloverleaf interchange with
US 41 Alternate, which provides access to Hopkinsville to the north and
Fort Campbell and
Clarksville, Tennessee, to the south. I-24 then crosses into Tennessee about later. Less than later is an interchange with the eastern terminus of
I-440, which is also accessible from I-40 nearby. Between I-40 and I-440, I-24's eastbound lanes are split into two barrier-separated carriageways to prevent weaving of traffic destined from I-40 to I-440. A short distance later is once again an interchange with SR 155 (Briley Parkway/Thompson Lane) near
Nashville International Airport. Beginning at the next exit,
SR 255 (Harding Place), the left lanes operate as
high-occupancy vehicle (HOV) lanes during rush hour. Over the next few miles, I-24 passes through the
Antioch neighborhood, where it has interchanges with Haywood Lane and
SR 254 (Bell Road), and crosses
Mill Creek. I-24 then continues through southeast Nashville, reaching interchanges with Hickory Hollow Parkway and
SR 171 (Old Hickory Boulevard). Upon reaching the top of the rim several miles later, the interstate has an interchange with US 41. later, the highway enters
Manchester, where it crosses the
Little Duck River and then has interchanges with
SR 53 and
SR 55 in short proximity. A short distance later, the highway reaches an interchange with US 41 once again. Leaving Manchester, the Interstate maintains its relatively straight trajectory and passes through the northeastern corner of
Arnold Air Force Base over a distance of about . The Interstate then travels over the next through a wide swath of mostly farmland, before entering
Grundy County and reaching an interchange with
US 64 and
SR 50 near the town of
Pelham, where it begins a concurrency with the former route that is largely unsigned. A short distance later, I-24 crosses the
Elk River, before reaching the base of the
Cumberland Plateau.
Monteagle Mountain and Cumberland Plateau gorge One of the most hazardous stretches of Interstate Highway in the US is located where I-24 crosses the Cumberland Plateau on steep grades in Grundy and
Marion County near the town of
Monteagle and is commonly known as "
Monteagle Mountain" or "Monteagle". While all motorists are advised to exercise caution along this stretch, truckers are particularly vexed by Monteagle, and many have died in accidents along this stretch. The eastbound grade is particularly hazardous, with a protracted four-to-six-percent grade over several miles. On this stretch, I-24 is three lanes in each direction and contains two
runaway truck ramps. Owing to geography, these two ramps are on the left side of the grade. The westbound downgrade of the plateau is also extremely hazardous and contains several sharp curves. Portions of this downgrade also feature offramp approach style lane dividers in order to slow motorists. Throughout the entire stretch across the Cumberland Plateau, the speed limit reduces to a maximum of and for trucks on both downgrades. At top of the Plateau, the Interstate surpasses in elevation, has interchanges with
US 41A and US 41, respectively, and crosses into
East Tennessee at the Grundy–Marion county line. The eastern Monteagle grade also has one of the three widest medians of any Interstate Highway; the others are
I-8 through the In-Ko-Pah grade in California and
I-84 through the Cabbage Hill grade east of
Pendleton, Oregon. There is more than between the eastbound and westbound lanes at one point. The eastbound lanes descend the hill on one side of Monteagle Mountain as part of the original three-lane (two ascending and one descending) US 64 alignment, while the westbound lanes ascend the other side of the hill on new roadbed built for that purpose. After descending Monteagle, I-24 travels for several miles through a vast flat gorge within the plateau characterized by long straightaways and few curves before reaching an interchange with
US 72 near
Kimball and
South Pittsburg, where US 64 splits off. This exit is the primary means of access to
Huntsville, Alabama, for motorists in East Tennessee. About later, the Interstate has an interchange with
SR 28 in
Jasper and crosses the
Sequatchie River. Beyond this point, the east and westbound lanes split more than apart over a few miles, encompassing farms, homes, and a few businesses in between. The route then crosses a large mountain ridge, has an interchange with
SR 27, and, about later, crosses the
Nickajack Lake impoundment of the
Tennessee River. Beyond this point, the highway travels through a narrow gorge over several miles, crossing the Running Water Creek and traveling under its namesake
trestle. This stretch is extremely crooked and can experience potentially strong
crosswind. The Interstate then enters
Hamilton County and the
Eastern Time Zone and then crosses into Georgia less than later.
Georgia and Chattanooga In the state of
Georgia, I-24 travels for in
Dade County along the southern flank of
Raccoon Mountain. Along this stretch, exits remain numbered according to Tennessee's mileage; however, the roadway mileposts are numbered according to Georgia's mileage. This segment also carries the unsigned SR 409 designation for internal
GDOT purposes. About after entering the state, the Interstate has an interchange with the northern terminus of
I-59, which provides access to
Birmingham, Alabama, to the southwest. The route then shifts north and has an interchange with
SR 299 in
Wildwood about later before turning back north and reentering Tennessee about later. Upon reentering Tennessee and Hamilton County, I-24 travels through
Tiftonia for several miles and has an interchange with
US 11/US 41/US 72 (Lee Highway) about later near the
Tiftonia neighborhood. About later, the Interstate curves sharply to the east, traveling on a narrow artificial causeway between the Tennessee River to the north and the northern tip of
Lookout Mountain to the south. A short distance later, the Interstate gradually curves 90 degrees to the north, entering
Chattanooga. Less than later is a three-way interchange with
US 27 (unsigned
I-124 northbound) northbound, which provides access to downtown Chattanooga directly to the north. Forming an unsigned concurrency with US 27, the highways sharply curve 90 degrees to the east, before widening to eight lanes. I-24 then briefly dips to the south, where it has a
trumpet interchange with a connector to
SR 8. A short distance later, US 27 splits off to the south at a near-cloverleaf interchange as Rossville Boulevard, where the Interstate reduces to six lanes. It then travels through the south side of Chattanooga before reaching a partial interchange with US 41/
US 76. Here, I-24 reaches the "Ridge Cut", a stretch where the Interstate ascends
Missionary Ridge on a steep grade, first curving sharply to the north at the bottom of the ascent and then to the east again at the top. This stretch is notorious for severe congestion and is especially hazardous to truckers. At the top of the Ridge Cut, the Interstate enters a straight section and begins a gradual descent over a short distance. Traveling roughly along the boundary between Chattanooga and
East Ridge, the Interstate has interchanges with multiple local thoroughfares over the next several miles. It then reaches its eastern terminus with I-75 at a
semi-directional T interchange, known locally as the "
75/24 Split" or simply "The Split". ==History==