Rocky Hill to Park City KY 255 begins at a junction with
KY 252 in Barren County, near the Rocky Hill community. The route is narrow and considerably curvy until coming to a junction with
KY 1297 about later. After this junction, the route straightens somewhat, proceeding north for another before coming to an intersection with the
concurrently running US 68/
KY 80 in the
Bon Ayr community. KY 255 widens somewhat past this point, continuing on for another mile before bridging the
Louie B. Nunn Cumberland Expressway via way of an overpass. The route then proceeds north for before coming to an intersection with
KY 1339. KY 255 then continues north for before being carried onto a bridge over a
CSX railroad track, the
Louisville and Nashville Railroad before intersecting
U.S. Route 31W. KY 255 previously passed the ruins of
Bells Tavern, and then intersected US 31W (Second Street) after a railroad crossing until 2012, when it was re-routed to go over the tracks via a new bridge on the west side of town. KY 255's concurrency with US 31W lasts , where KY 255 turns left onto
Mammoth Cave Parkway. Its original concurrency with US 31W lasted for .
Mammoth Cave National Park and northwestern Barren County After its brief concurrency with US 31W, KY 255 branches north, going before intersecting with
Interstate 65 (I-65) at its Exit 48 interchange. After this intersection, KY 255 continues in a northwesterly path and enters
Mammoth Cave National Park; the southern entrance of the park is approximately north of the Interstate. It proceeds north for another 0.9 miles, passing Diamond Caverns before entering the far eastern portion of
Edmonson County and reaching its first intersection with KY 70 in the southern part of the park near the site of a former town named
Chaumont. This was KY 255's original northern terminus from the 1930s until sometime in the mid-1970s. At that point, KY 255 joins KY 70 by making a right turn eastward to re-enter Barren County. This concurrency lasts for before reaching an intersection in
Highland Springs, where KY 255 turns left, while KY 70 turns right to head for
Cave City. KY 255's current northern terminus is located near the Sand Cave Trail at the southeastern entrance into the Mammoth Cave National Park; that point marks the end of state maintenance. KY 255's final segment between Highland Springs and the northern terminus is part of the
Cordell Hull Scenic Highway, part of the
Kentucky Scenic Byways system. ==History==