Several years ago, driving across New Mexico, I looked at my map and saw US Highway 666 extending northward from I-40 into Colorado. I dropped everything, got my camera ready, and hurried to it, only to discover it was gone: a bunch of killjoys renamed it to US 491 in 2003, and my map was outdated.
But all is not lost. In northwestern Pennsylvania, cutting through the middle of Allegheny National Forest, is State Highway 666. So, you can still drive the highway to Hell.