The Collaborative International Dictionary
                    Guideboard
                    
                        
                
                                                                    Guideboard \Guide"board`\, n.
   A board, as upon a guidepost having upon it directions or
   information as to the road. 
--Lowell.
Wiktionary
                    guideboard
                    
                        
                
                                                                    n. A board, as upon a guidepost bearing road directions.
Usage examples of "guideboard".
Boone, the county seat of Watauga County, was our destination, and, ever since morning, the guideboards and the trend of the roads had notified us that everything in this region tends towards Boone as a center of interest.