U.S. Route 42

U.S. Route 42 is an east–west United States highway that runs northeast-southwest for 355 miles (571 km) from Cleveland, Ohio to Louisville, Kentucky. The route has several names including Pearl Road from Cleveland to Medina in Northeast Ohio, Reading Road in Cincinnati, Cincinnati and Lebanon Pike in southwestern Ohio and Brownsboro Road in Louisville, Kentucky. Traveling east, the highway ends in Downtown Cleveland, Ohio; and traveling west it ends in Louisville, Kentucky.

Interstate 71 fully supplanted US 42 as an interurban highway in the early 1960s, relegating US 42 to its current role as an ordinary town-to-town surface road. Unlike I-71, US 42 avoided Columbus completely. It remains intact as a route; no part of it has ever been diverted to any Interstate highway. It is not the "parent" of any US route with a related number.

In spite of its even number, US 42 is posted north-south from Fort Mitchell, Kentucky northward.