This wall is in Holbrook, AZ. It fills a couple of outside walls of a shuttered restaurant, and appears to stretch at least as far from end to end as the self-proclaimed "World's Longest Map of Route 66" further west in Meteor City.
The "map" is the usual cartoon ribbon of black paint as the highway. One wall labels major (for Route 66) cities from the west coast east to Chicago. The other, more Arizona-focused mural emphasizes the importance of petrified wood in the sweeping pageantry that is Route 66 -- after all, Holbrook is Petrified Wood Central. As with most mural maps, don't trust scale, distance, or north-south orientation. "Home of Gertie" the dinosaur may be further from the "Agate House" than is suggested here.