SR 9 begins in Cocke County at North Carolina-Tennessee state line near Del Rio, concurrent with US 25/US 70. US 25/US 70/SR 9 then goes through some curves and cross Wolf Creek via the Wolf Creek Bridge. They then begin running along the north bank of Wolf Creek and intersect and become concurrent with SR 107 and then enter Del Rio, where SR 107 separates. US 25/US 70/SR 9 continue northwest to intersect SR 340 before leaving Del Rio. They then cross Wolf Creek again and before entering Newport and leaving Wolf Creek and crossing the Pigeon River. In Newport, they intersect SR 73 before entering downtown. In downtown, they intersect and become concurrent with US 321 and SR 35. US 321 separates shortly afterwards at the intersection with SR 32, where US 321 goes south on SR 32 and SR 32 joins the concurrency. US 25/US 70/SR 9/SR 35 then leave downtown and come to where US 25 splits into US 25W and US 25E. Here, SR 32 goes north on US 25E and US 70/SR 9/SR 35 continue on US 25W. US 411 also begins at this intersection and joins the concurrency. The concurrency then has a full interchange with I-40 before US 411/SR 35 separate and turn south. US 25W/US 70/SR 9 then leave Newport and cross into Jefferson County. Immediately after crossing the line, they intersect SR 363. They then cross Douglas Lake, parallel to the I-40 bridge. Immediately after crossing the lake, they intersect SR 113. They then enter Dandridge and become concurrent with SR 66. US 25W/US 70/SR 9/SR 66 then intersect and become concurrent with SR 92, passing by downtown to the north and SR 66 becoming unsigned at this intersection. They then separate from SR 92 and have another interchange with I-40, with SR 66 separating and having an unsigned concurrency with I-40 west before leaving Dandridge. They then continue west through rural Jefferson County before coming to an intersection with Snyder Road (which conncects to SR 66 and Sevierville) and SR 139, becoming concurrent with SR 139 before crossing into Sevier County. Once across the line, SR 139 separates and turns south towards Kodak, and US 25W/US 70/SR 9 continue west to cross into Knox County. They then have an interchange with US 11E/SR 34, with them joining the concurrency as they enter Knoxville. US 11E/US 25W/US 70/SR 9/SR 34 then intersect SR 168 before having another interchange with I-40, where SR 9 and US 25W run concurrentwith for a short ways before concurrent with I-640. They then have interchanges with Mall Road (which provides access to Knoxville Center Mall), US 441/SR 33/SR 331 (which provides access to Fountain City), and I-75/I-275 before separating and US 25W/SR 9 turns north. They continue through the North Knoxville neighborhood and then leave Knoxville to enter Powell. In Powell, they intersect and have a short concurrency with SR 131 before leaving Powell and crossing into Anderson County, entering Claxton and becoming a very curvy 4-lane undivided highway. In Claxton, US 25W/SR 9 intersects SR 170, then continues north and leaves Claxton before entering Clinton. In Clinton, they intersect SR 61 before going straight through the historic downtown as Main Street. They then leave Clinton and become curvy again before going through Medford to enter Rocky Top (Lake City). In Rocky Top, US 25W/SR 9 go through downtown and intersect and become concurrent with SR 116. They then intersect US 441/SR 71 (which provides access to Norris Lake and Norris Dam). They then have an interchange and US 25W/SR 9 becomes concurrent with I-75, with SR 116 taking over the old route of US 25W/SR 9. They then cross into Campbell County and enter Caryville, where they separate from I-75 and become concurrent with SR 63. Immediately afterward, they intersect the northern end of SR 116 and pass by Cove Lake, Cove Lake State Park, and Caryville Dam before leaving Caryville and entering Jacksboro. In Jacksboro, US 25W/SR 9/SR 63 bypass downtown to the north and go through Jacksboro's main business area. They then leave Jacksboro and enter La Follette. In La Follette, they go straight through downtown and then US 25W/SR 9 separate from SR 63 and leave La Follette, becoming very curvy again. It then passes through Duff and Habersham before entering Morley and intersecting SR 90. The then finally enter Jellico and have another interchange with I-75. US 25W/SR 9 then enter downtown and intersect SR 297 before turning north and ending at the Kentucky state line, with US 25W continuing north alone into Kentucky.