| State: | KY |
| Type: | KY |
| Route: | 21 |
| Map Custom: | yes |
| Maint: | KYTC |
| Length Mi: | 17.284 |
| Length Round: | 3 |
| Length Ref: | [1] |
| Direction A: | West |
| Terminus A: | near Paint Lick |
| Junction: | in Berea in Berea in Bighill |
| Direction B: | East |
| Terminus B: | Jackson County line |
| Counties: | Madison |
| Previous Type: | KY |
| Previous Route: | 20 |
| Next Type: | KY |
| Next Route: | 22 |
Kentucky Route 21 (KY 21) is a 14.196miles west–east highway in Madison County, running from the Garrard County line near Paint Lick to Bighill, east of Berea.
It begins at KY 52 at the Garrard County line at the Paint Lick Creek Bridge. The road passes through Wallaceton and traverses over Interstate 75 in Berea, where KY 21 shortly runs along with US 25. After US 25 breaks away and goes north toward the Blue Grass Army Depot, KY 21 continues to the east and intersects US 421 in Bighill before ending at the Jackson County line.
KY 21 begins at an intersection with KY 52 near Paint Lick in Madison County, heading southeast as two-lane undivided Paint Lick Road. The road passes through farmland with some trees and homes, curving south before heading back to the southeast. The route continues south and then southeast through more rural areas and comes to an intersection with the eastern terminus of KY 954. Following this, KY 21 heads east into wooded areas with some fields and residences, curving to the northeast. The road heads into Berea and enters commercial areas, curving east and coming to an interchange with I-75, at which point it is five lanes wide with a center left-turn lane. Past this interchange, the route becomes Chestnut Street and becomes a four-lane divided highway, intersecting US 25.[1]
At this point, US 25 joins KY 21 for a concurrency and the two routes pass through residential areas as a two-lane undivided road. The road passes over a CSX railroad line and heads northeast into the downtown area of Berea before it passes more homes. KY 21 splits from US 25 by heading east on Prospect Street and immediately intersects KY 595. The road runs through more residential areas with some businesses and curves to the southeast. The route becomes Big Hill Road and curves east to leave Berea, heading through farmland with some homes and crossing KY 1617. KY 21 turns to the southeast and continues east through dense forests with some fields and residences. The route continues east to US 421 in Bighill, where it turns south to form a short concurrency with that route on McKee Road before heading east on Owsley Fork Road. KY 21 passes through more farmland and woodland and winds southeast to its eastern terminus at the county line between Madison County and Jackson County.[1]