rt138State Route 138 (SR 138) is an east–west state hhway in the U.S. state of California that generally follows the northern foothills of the San Gabriel Mountains and the western MojaveCrossing Sainte-Anne-de-la-Pérade (Chemin du Roy). Route 138 is a major hhway in the Canadian province of Quebec, following the entire north shore of the St. Lawrence River past