U.S. Route 421 in Kentucky
| US 421 highlighted in red | ||||
| Route information | ||||
| Maintained by KYTC | ||||
| Length | 250.536 mi (403.199 km) | |||
| Major junctions | ||||
| South end | US 421 at the Virginia state line near Pennington Gap, VA | |||
| North end | US 421 at the Indiana state line near Madison | |||
| Location | ||||
| Country | United States | |||
| State | Kentucky | |||
| Counties | Harlan, Leslie, Clay, Jackson, Rockcastle, Madison, Fayette, Scott, Woodford, Franklin, Shelby, Henry, Trimble | |||
| Highway system | ||||
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U.S. Route 421 (US 421) in the U.S. state of Kentucky is a 250.536-mile-long (403.199 km) north–south United States highway that traverses twelve counties in the central and eastern parts of the state. It travels in a southeast-to-northwest path from the Virginia state line near Pennington Gap to the Indiana state line, on the Ohio River at Milton, Kentucky and Madison, Indiana.