cross-posted from: https://lemmy.ml/post/55188993

From Names to Numbers: The Origins of the U.S. Numbered Highway System by Richard F. Weingroff, Information Liaison Specialist, Federal Highway Administration

Map of the final U.S. Highway system as approved November 11, 1926 (8,972 × 5,851 pixels, file size: 18.59 MB)

https://en.wikipedia.org/wiki/American_Association_of_State_Highway_and_Transportation_Officials