Kentucky Route 40 (KY 40) is a state highway in the U.S. state of Kentucky. The road begins at a junction with U.S. Route 460 / KY 7 in Salyersville in Magoffin County, then continues eastward through Paintsville in Johnson County. KY 40 ends in Martin County at an intersection with KY 292 and an access bridge to US 52 at the West Virginia border. The road was featured during the 1980s in a song by Ricky Skaggs, "Highway 40 Blues".KY 40 originally extended west to Frankfort.