U.S. Route 27 in Tennessee

Beginning at I-24, and ending at State Route 111 (SR 111), the route is a controlled-access highway for approximately 24 miles (39 km). The highway goes north as a narrow four-lane freeway (concurrent with unsigned I-124) through downtown and has interchanges with West Main Street (Exit 1), Martin Luther King Boulevard (Exit 1 A/B; unsigned SR 316), and Fourth Street (Exit 1C; unsigned SR 389) before crossing the Tennessee River on the P.R. Olgiati Bridge, where it widens to eight lanes and unsigned I-124 ends. It then has interchanges with Manufacturer's Road and Dayton Boulevard (Old US 27; unsigned SR 8) before crossing Stringer's Ridge to have an interchange with the national southern terminus of US 27's only auxiliary route, US 127, which is where SR 27 splits off to go north on that route. From here, the route is part of Corridor J of the Appalachian Development Highway System. US 27/SR 29 then narrow to six lanes and runs on top of a ridge while passing through Red Bank, where it has interchanges with Morrison Springs Road, where it narrows to four lanes, Mountain Creek Road, SR 153 southbound and Dayton Pike northbound (once again, the old route of US 27), before entering Soddy Daisy. The route continues north with interchanges at Thrasher Pike and Harrison Lane before having an interchange at Sequoyah Access Road, the main route to the Sequoyah Nuclear Power Plant. It then has an interchange with SR 319 (Hixson Pike) before running along the Tennessee river to a massive interchange with SR 111, which splits off to the northwest for Dunlap, where the freeway ends. The freeway continues along SR 111.

US 27 at its intersection with SR 303, in Rhea County near Graysville

US 27 continues as a four-lane divided highway through the small towns of Sale Creek and Graysville, where it intersects with SR 303, before crossing into Rhea County, and reaching Graysville. The route then enters Dayton at the intersection with SR 378 (Market Street; Old US 27) and SR 60 (Hiwassee Highway). It bypasses downtown to the east and intersects SR 30. US 27 then has another intersection with SR 378 before it leaves Dayton and continues northward through Evensville before becoming concurrent with SR 68 and arriving at Spring City. It then has an interchange where SR 68 splits off to the west, while US 27 enters downtown and intersects with SR 302. It then leaves Spring City and continues north through farmland.

U.S. Route 27 at its Richland Creek crossings in Dayton

U.S. Route 27 in Evensville. The Cumberland Plateau is on the right.

From here, US 27 enters Roane County and runs through Glen Alice before becoming concurrent with US 70/SR 1 and entering the city of Rockwood. They go straight through town, passing just east of downtown before US 70 splits to the east, taking SR 1 and SR 29 with it. US 27 then runs concurrently with SR 61 (which is signed, except on I-40), as that highway begins here. US 27/SR 61 then pass through Cardiff, where they intersect with the short SR 382, which provides access to Roane State Community College. They then enter Harriman, and pass through countryside before coming to an interchange with I-40 (Exit 347). During this stretch, it forms part of the Harvey H. Hannah Memorial Highway, and is signed as such. They then enter the South Harriman neighborhood and pass by several businesses and rejoin with SR 29 (Ruritain Road). They then cross the bridge over the Emory River to enter and pass through the historic downtown, intersecting with SR 328. Just beyond Harriman, near the DeArmond community, US 27/SR 29 then splits from SR 61 at an interchange, with the Harvey H. Hannah Memorial Highway following that route to the east. US 27/SR 29 then begin to ascend the Cumberland Plateau as it then narrows to two lanes, and continues northward across the plateau for its remaining 55 miles (89 km) or so in Tennessee.

View of Wartburg, Tennessee. Lone Mountain is in the background on the left. U.S. Route 27 is below.

In Morgan County, the highway passes through the rugged mountains of the Cumberland Plateau and has another intersection with SR 328 before ascending a ridge to enter Mossy Grove. It passes through Mossy Grove and has an intersection with Clayton Howard Road, which provides access to Lone Mountain State Forest. It then leaves the town and continues north to an intersection with Main Street (Old US 27 in Downtown) just before entering Wartburg. US 27/SR 29 then widen to 4 lanes just before the intersection with SR 62 and becomes concurrent with that route. They go north, bypassing downtown to the east before leaving Wartburg at the intersection with Old Gobey Road, which heads off to Gobey. The highway then descends down a mountain and narrows to 2 lanes once again just before another crossing of the Emory River. They then have an intersection with Gobey Road, another access road to Gobey, before SR 62 splits off to the west. US 27/SR 29 then becomes narrow, curvy, and winding as it passes through rural areas. With nowhere to pass a slow car, the highway passes by the Morgan County fairgrounds before passing through the town of Annadel. It does not have any passing lanes before entering the town of Sunbright. US 27/SR 29 passes through the center of town, having Intersections with SR 329 and Burrville Road, an access road to Burrville. It then becomes even curvier as it leaves Morgan County to cross into Scott County. For the next 12 miles (19 km) it has one place to pass with a 40 miles per hour (64 km/h) speed limit. US 27/SR 29 then passes through the community of Glenmary before entering Elgin, where the highway intersects SR 52, which connects the area with the historic village of Rugby and Fentress County to the west.

US 27 (Alberta Street) in Oneida, Tennessee

U.S. Route 27 south of Huntsville in Scott County.

Beyond Elgin, US 27/SR 29 passes through Robbins, the county seat of Huntsville (where it intersects with SR 63, becomes concurrent with SR 297, and widens to 4 lanes), and Helenwood before reaching the city of Oneida.

In Oneida, the highway passes through a major business district before narrowing to 2 lanes again before entering downtown and having an intersection with SR 456 just before passing by Big South Fork Medical Center. SR 297 then splits off to the west in the center of town, which provides access to the Big South Fork National River and Recreation Area. US 27/SR 29 then passes through the rest of downtown before leaving Oneida and passes through Winfield, the last sizable town that US 27 passes through in Tennessee before it reaches the community of Isham on the Kentucky border, where SR 29 ends and US 27 continues north into McCreary County.

U.S. Route 27 at the Tennessee-Kentucky state line, looking south into Scott County from McCreary County, Kentucky. The shop on the right sits near the border and allows Tennessee residents to take advantage of Kentucky's lower state sales tax on cigarettes.

(This only applies to the standalone portion)

The entire route is in Roane County.

Location	mi	km	Destinations	Notes
Rockwood			US 27 north / US 70 / SR 61 east (Gateway Boulevard/SR 1) – Downtown, Harriman	Northern end US 27 concurrency; western terminus of SR 61; SR 61 takes over concurrency with US 27 though it is signed
​			SR 382 north (Patton Lane)	Southern terminus of SR 382; provides access to Roane State Community College
Midtown			Ruritain Road (Old SR 29)
			US 70 east (Roane State Highway/SR 1 east) – Kingston	Northern end of US 70/SR 1 concurrency; begin signed portion of SR 29; SR 29 becomes secondary
			I-40 – Nashville, Knoxville	I-40 exit 350
Harriman			Ruritain Road (Old SR 29)
			US 27 south / SR 61 west (S Roane Street) – Rockwood	Southern end of US 27/SR 61 concurrency; end signed portion of SR 29; SR 29 becomes primary
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus