Interstate 24

I-24 begins at exit 44 on I-57 in southern Williamson County, near the community of Pulleys Mill.[3] 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 U.S. 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.[4] 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 Interstate 24 Bridge over the Ohio River. After that, it continues into Kentucky.[5]

I-24 crosses into Kentucky on a bridge over the Ohio River. It passes to the west of Paducah and intersects US 60, US 45, and US 62. The freeway then passes near Woodlawn-Oakdale and Reidland and connects with US 68. The welcome center in Paducah is a historic house, Whitehaven. This is the only historic house in the country used as a rest area. East of this point, I-24 runs concurrently with I-69. Through this, it intersects US 62 and crosses the Tennessee and the Cumberland Rivers. The roadway travels along the north shore of the Cumberland River.

I-69 splits off to the east just north of Mineral Mound State Park. I-24 continues east, away from the river. It runs through farmland for several miles. It passes south of Hopkinsville and interchanges with I-169. Near the Tennessee border, I-24 passes north of Fort Campbell. Afterward, it crosses into Tennessee.[6]

I-24 in Nashville

I-24 crosses into Tennessee traveling in a southeasterly and northwesterly direction in Clarksville, Montgomery County. The first interchange is with State Route 48 (SR 48). I-24 then has interchanges with US 79, SR 237, and SR 76, and crosses the Red River. It then enters a long straight section with several steep grades, crossing into Robertson County, and has interchanges with SR 256, and SR 49 near Springfield, respectively. The route then enters the rolling hilly terrain of the Nashville Basin, and crosses briefly into Cheatham County, where it has an interchange with SR 249. I-24 then crosses into Davidson County, and has an interchange with US 431. The Interstate continues for several miles through rural woodlands and multiple steep grades before coming to an interchange with SR 45 (Old Hickory Boulevard).

After I-24 crosses the Nashville Urban Boundary, it widens to six lanes and has an interchange with SR 155 (Briley Parkway), the northern beltway around Nashville. Shortly thereafter, I-24 joins a concurrency with I-65, where the combined routes carry ten through lanes, and travel south. There is an interchange with US 431 (Trinity Lane) near the midpoint of the I-24/I-65 concurrency. I-65 splits off to the west and I-24 enters downtown Nashville, where it has interchanges with US 41, US 431, and US 31E, as well as several city streets. I-24 then crosses the Cumberland River on the Silliman Evans Bridge. After crossing the river, I-24 joins I-40 and the two highways travel southeast along eight through lanes for 2 miles (3.2 km). I-40 splits off eastwardly and heads toward Knoxville. Just to the south is another interchange with US 41/US 70S. Soon after is another interchange with the eastern terminus of I-440. I-24 meets SR 155/Briley Parkway again near the Nashville International Airport. Southeast of here, the road has eight through lanes. Beginning at the SR 255 exit, the left lanes operate as HOV lanes during rush hour. Over the next few miles, I-24 has interchanges with Haywood Lane, SR 254 (Bell Road), Hickory Hollow Parkway, and SR 171 (Old Hickory Boulevard).

I-24 continues southeast through the suburbs of Nashville and crosses into Rutherford County near the city of LaVergne, where it has an interchange with a connector road to that city. Beginning at this point, I-24 is relatively straight and flat for most of its distance through Middle Tennessee. The straightest stretch of highway in Tennessee is located on I-24 between Lavergne and eastern Murfreesboro, where the route is perfectly straight for about 15 miles (24 km), although the median widens and narrows. As it reaches Smyrna there is an interchange with SR 266 (Sam Ridley Parkway) and another with SR 102 (Almaville Road), which also serves a Nissan Smyrna Assembly Plant. Four miles (6.4 km) later is an interchange with I-840, the outer southern beltway around Nashville. Beyond this point, I-24 enters Murfreesboro, the largest suburb of Nashville. There, I-24 has interchanges with SR 96 which connects to Franklin, SR 99 (New Salem Highway), and US  231 which connects to Lebanon and Shelbyville, respectively. At the US 231 exit, the HOV lane designation ends and I-24 narrows to six lanes and then to four lanes a short distance later. An interchange with the Joe B. Jackson Parkway lies on the outskirts of Murfreesboro.

I-24 then enters a more rural area, and remains relatively straight for many miles. Around milepost 96, I-24 briefly enters Bedford County and then Coffee County. At exit 97, it has an interchange with SR 64, which connects to Shelbyville. I-24 then gently curves to the south then the east and meets US 41. Later, I-24 enters Manchester, where it has interchanges with SR 53, SR 55, and US 41, respectively. I-24 continues through a rural, largely agricultural area where it crosses into Grundy County and has an interchange with US 64 and SR 50.

One of the most hazardous stretches of Interstate Highway in the United States is located approximately 40 miles (64 km) west of Chattanooga on I-24 in Monteagle, where the highway crosses the Cumberland Plateau. The eastbound grade is particularly hazardous, with a protracted 4–6% grade over several miles. Compared to grades elsewhere in the state, this downgrade does not come close to the steepest (I-40 between Nashville and Knoxville features 5% grades in each direction as well as a 5% grade north of Nashville on I-24, near Joelton). 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 both motorists and truckers. Throughout the entire stretch across the Cumberland Plateau, the speed limit reduces to a maximum of 55 mph (89 km/h); the westbound downgrade contains a 45 mph (72 km/h) speed limit for trucks. On the eastbound downgrade, the speed limits for vehicles and trucks are 45 and 35 mph (72 and 56 km/h), respectively.

Westbound I-24 at the US 72 interchange

After crossing Monteagle Mountain, I-24 travels for several miles through a vast flat gorge characterized by long straightaways and few curves before reaching an interchange with US 72 near Kimball and South Pittsburg. In Jasper, I-24 has an interchange with SR 28. Beyond this point, the east and westbound lanes split more than 0.5 miles (800 m) apart, encompassing farms, homes, and a few businesses in between. This was reportedly a result of extensively fought disputes over right-of-way acquisitions, and is also one of the widest medians of any highway. The route then crosses a large hill, has an interchange with SR 27 and crosses the Nickajack Lake impoundment of the Tennessee River. Beyond this point, I-24 travels through another narrow gorge, crossing the Running Water Creek and traveling under its namesake trestle. I-24 can experience potentially strong crosswinds for several miles along this segment. I-24 briefly enters Hamilton County and the Eastern Time Zone and then crosses into Georgia.

In the state of Georgia, I-24 travels along the southern flank of Raccoon Mountain. Shortly after entering the state, I-24 has an interchange with the northern terminus of I-59. The route then turns north, and has an interchange with State Route 299 (SR 299) in Wildwood before turning back north and reentering Tennessee. In Georgia, the exits remain numbered according to Tennessee's mileposts; however, the roadway mileposts are numbered according to Georgia's mileposts.[7]

Upon reentering Tennessee and Hamilton County, I-24 travels through Lookout Valley for several miles, and has interchanges with several key roads, including US 11/US 41/US 72. Several miles later, I-24 curves sharply to the east, traveling on a narrow causeway between the Tennessee River and the northern tip of Lookout Mountain. Entering Chattanooga, there is a three-way interchange with US 27 (unsigned I-124) northbound, which is a freeway beyond this point. Forming a concurrency with US 27, the highways then curve sharply to the east, then to the west where US 27 splits off to the south as Rossville Boulevard. With interchanges with several city streets, I-24 travels through the inner city of Chattanooga. Between the 4th Avenue exit and the Germantown/Belvoir exit, I-24 reaches the "Ridge Cut", a 0.25-mile (400 m) section of Missionary Ridge where the Interstate climbs the ridge and curves sharply to the north and then to the east again. Accidents and severe congestion are common here. At the top of the Ridge Cut, I-24 enters a relatively flat and straight section, and, after a few interchanges with surface streets, reaches its eastern terminus with I-75 in East Ridge.

The section of I-24 between Nashville and Chattanooga was part of the original Interstate Highway System plan enacted in 1956.[8] Two of the first sections of I-24, both in Tennessee, began construction in 1958. These included the section between downtown Nashville and the Rutherford County line, and the eastern terminus with I-75.

In Tennessee, I-24 was constructed in segments. In Chattanooga, the Interstate was complete through the central part of town in 1963, and the rest of the city in 1965. The Ridgecut section, the final section, was dedicated on December 1 of that year.[9] The segment at the foot of Lookout Mountain was completed on December 16, 1966.[10] In Nashville, the segment between the split with I-40 and the split with I-65 (then I-265) was dedicated on January 14, 1964.[11] I-24 was complete in Marion County to Monteagle Mountain in 1966 and between US 41 in Manchester and US 64 near Pelham on July 27, 1967.[12] The bridge over Nickajack Lake opened on December 18, 1967.[13] I-24 was constructed over Monteagle Mountain between 1962 and 1968.[14] On December 9, 1970, I-24 opened between US 231 in Murfreesboro and SR 64.[15] The route was opened between SR 171 in Nashville and US 231 in Murfreesboro on December 31, 1970.[16] The last segment of I-24 between Nashville and Chattanooga, the segment located between SR 64 near Beechgrove and US 41 northwest of Manchester, was opened and dedicated on December 16, 1971.[17] Work began on I-24 from the Kentucky line through Clarksville in 1970, and construction on the entirety of I-24 between Clarksville and Nashville was underway by 1972, with an estimated completion date of late 1974 or early 1975.[18] Construction on this approximately 44-mile (71 km) segment, the last segment of mainline Interstate Highway completed in Tennessee, proved to be difficult due to the rugged and hilly terrain.[19] The approximately 32-mile (51 km) segment between US 68 in Hopkinsville, Kentucky, and US 79 in Clarksville, Tennessee, was jointly opened to traffic by both states on September 12, 1975.[20][21] The 15-mile (24 km) section between US 79 and SR 49 in Robertson County was completed in September 1976.[22] The last segment of I-24 in Tennessee, between SR 49 and I-65 in Nashville, was opened to traffic on January 7, 1978, more than two years behind schedule.[18][23]

In Georgia, I-24 opened between the interchange with I-59 and the eastern border with Tennessee, along with the eight-northernmost-miles (13 km) of I-59, on September 10, 1968.[24]

I-24 Bridge connecting Illinois with Kentucky across the Ohio River

In Kentucky, I-24 broke ground in December 1967 in Lyon County. The Ohio River Bridge opened in October 1974 at a cost of $18.6 million (equivalent to $77.4 million in 2022[25]).[26] The section of I-24 in Illinois was authorized for engineering by 1966 and authorized for construction by 1968.[8][27] The final segment in Illinois opened to traffic in late January 1976 at a cost of $32.5 million (equivalent to $117 million in 2022[25]).[28] I-24 was completed when a 23-mile (37 km) section opened to traffic from Western Kentucky Parkway to US 68 east of Cadiz, Kentucky, on May 23, 1980.[29]

In 1979, structural problems were discovered on the Ohio River Bridge, including 119 cracks as a result of defective welding in the tie girders.[30] The bridge was closed on August 3, 1979, and remained closed to all traffic through October 1980 and all truck traffic until the summer of 1981.[31]

Since its completion, I-24 has seen many upgrades. The approximately 9.3-mile (15.0 km) segment between Haywood Lane in Nashville and SR 266 in Smyrna was widened from four to eight lanes between June 1997 and December 1998, installing the first HOV lanes on I-24.[32] The 8.2-mile (13.2 km) portion between SR 266 and I-840 was widened from four to eight lanes between August 1998 and November 2000. The four-mile (6.4 km) segment between I-440 and Haywood Lane was widened from three to four lanes in each direction between March 2000 and May 2002 in a project that also improved the interchanges on this segment.[33] Widening of the segment between I-840 and SR 96 began in early 2004 and was completed in the summer of 2005.[34] This project added a new interchange at Medical Center Parkway. A project that widened I-24 from four to eight lanes between SR 96 and US 231, and also added a new interchange with SR 99, began in April 2006 and was completed on January 28, 2008.[35]

On May 18, 2010, it was announced that a sinkhole was found near exit 127 (Pelham) in the eastbound lanes of I-24 in Grundy County, Tennessee, near the exit to SR 50. Tennessee Department of Transportation officials stated that the hole was growing and diverted traffic onto the westbound lanes.[36] Following emergency repairs, the highway was reopened several days later.[37]

Interstate 124 (I-124) is an unsigned designation for a short segment of US 27 freeway in Chattanooga, Tennessee.

Interstate 24 Business Loop (I-24 Bus.) is an 11-mile (18 km) business loop of I-24 that travels through downtown Paducah, Kentucky, that begins at I-24 and US 60 at exit 4 and ends at I-24 and Kentucky Route 1954 (KY 1954) at exit 11. Originally designated as the I-24 Downtown Loop (I-24 Dwtn.), the route was repurposed as I-24 Bus. in 2002. The highway follows US 60, Business U.S. Route 60 (Bus. US 60), and KY 1954.

Major Intersections

The entire route is in McCracken County.

Location	mi[42]	km	Destinations	Notes
Paducah	0.0	0.0	US 60 west (Hinkleville Road west) / I-24	Western terminus; western end of US 60 concurrency; I-24 exit 4
	1.9	3.1	KY 731 south (32nd Street)	Northern terminus of KY 731
	2.4	3.9	US 60 east (Joe Clifton Drive) / US 60 Bus. begin	Eastern end of US 60 concurrency; western end of US 60 Bus. concurrency; serves Baptist Health Paducah
	2.6	4.2	US 45 (H.C. Mathis Drive)
	4.4	7.1	US 45 Bus. north (8th Street)	Western end of US 45 Bus. concurrency
	5.2	8.4	US 45 Bus. south (Kentucky Avenue)	Eastern end of US 45 Bus. concurrency
	8.2	13.2	US 60 Bus. ends / KY 1954 begin / US 60 / US 62	Eastern end of US 60 Bus. concurrency; western end of KY 1954 concurrency
Woodlawn-Oakdale	8.8	14.2	KY 450
	10.9	17.5	KY 2187 north (Husband Road north)	Southern terminus of KY 2187
​	11.2	18.0	KY 1954 east (Husband Road) / I-24 – Kentucky Dam, Nashville, St. Louis	Eastern terminus; eastern end of KY 1954 concurrency; I-24 exit 11
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus