Greene County SR 70 begins in
Greene County as a primary highway at the
North Carolina border, with the highway continuing as
North Carolina Highway 208 (NC 208). It begins as a curvy two-lane highway, going through the mountains along the Tennessee - North Carolina border. It goes west, crossing the
Appalachian Trail a few hundred feet across the border before going through some mountains before lowering down into the farmland of Greene County and turning north, straightening and widening into a two-lane rural highway with a speed limit of . SR 70 then enters the community of
South Greene and coming to a Y-intersection with
SR 107, becoming concurrent with that route. They then come to an intersection with
SR 351 (which is also Tennessee State Route 107 Cutoff, an auxiliary Route of SR 107) before leaving South Greene at a crossing of the
Nolichucky River, just a few yards away from the historic
Nolichucky Dam and its reservoir,
Davy Crockett Lake. SR 70/SR 107 continue north through some farmland before entering
Greeneville. They go through some suburbs and pass by a few businesses before coming to an intersection with
US 321/
SR 35, with the SR 107 separating to follow that route northeast into downtown, all the while SR 70 completely bypasses downtown to the south. SR 70 then widens to four lanes, through undivided, and goes to intersect and become concurrent with
US 11E Bus/
SR 350, turning west. They then come to major interchange with
US 11E/
SR 34 (
Andrew Johnson Highway), where US 11E Bus/SR 350 both end and SR 70 becomes concurrent with US 11E/SR 34, turning east as a four-lane divided highway, with the road continuing as
Blue Springs Parkway (Old US 11E). Shortly afterwards, they come to another intersection, where SR 70 separates and turns north, returning to a two-lane highway and leaving Greeneville. It then becomes narrow and curvy again as it goes through more farmland. It then makes a sharp right turn at an intersection with a county road (
Marvin Road) before continuing north for about before coming to an interchange with
I-81 (Exit 30). It then come to a T-intersection with
Horton Highway, a major county road the connects the highway to the town of
Baileyton, the community of
Fall Branch, and
SR 93. It then turns left to go west around a mountain before going down a narrow valley before weaving through some mountains and crossing into
Hawkins County.
Hawkins County SR 70 then weaves through some more mountains before finally turning west to enter farmland again and widen and straighten into a two-lane rural highway with a speed limit of . It then intersects with
Old Highway 70, the narrow and curvy former alignment of SR 70 through the area before it was realigned onto a new highway. It then continues west before entering and going through the town of
Persia before coming to an intersection and becoming concurrent with
SR 66, just north of that route's intersection with
SR 113. They then go north and catch-up with the other end of Old Highway 70 before crossing a bridge over the
Holston River/
Cherokee Lake. They then enter
Rogersville and pass through a business district and some neighborhoods before coming to an interchange with Main Street (Old US 11W), which connects the highway to downtown to the northeast as SR 66/SR 70 bypass it to the southwest. They then come to an interchange with
US 11W/
SR 1 (Lee Highway/Memphis to Bristol Highway), where SR 70 separates to become concurrent with US 11W/SR 1 to the northeast while SR 66 continues north as curvy and narrow secondary highway towards
Sneedville. They then pass along the northern edge of downtown, as a four-lane divided highway, before coming to an interchange with
SR 347 (Main Street/Old US 11W), where SR 347 ends and SR 70 separates to take over that route and it goes north as a narrow and curvy two-lane highway through both mountains and farmland before coming to an intersection with
SR 94 (Pressmen's Home Road), which runs through the abandoned town of
Pressmen's Home, before entering a long mountain pass over several mountains and ridges before crossing into
Hancock County just north of the community of
Edison.
Hancock County SR 70 then winds its way along the banks of the
Clinch River before crossing it along the historic
Kyles Ford Bridge and entering
Kyles Ford. It then immediately has an intersection and concurrency with
SR 33 as they go through the heart of the community before separating with SR 33 turning southwest towards
Sneedville while SR 70 continues north, becoming a secondary highway and going through some countryside before crossing the
Virginia state line and continuing as
Virginia State Route 70 (Trail of the Lonesome Pine) towards
Jonesville. ==History==