County Route 66 is a county-maintained roadway located within San Bernardino County, California. Its designation as "66" directly references its historical alignment as a segment of the former U.S. Route 66, often referred to as "The Mother Road."
Following the decertification of U.S. Route 66 in 1985, many portions of its original path were transferred to state, county, or local jurisdiction. In San Bernardino County, multiple stretches of the former federal highway were re-designated as county routes, including various sections now collectively or individually known as County Route 66. These segments are vital in preserving the legacy of U.S. Route 66, which played a significant role in American transportation and culture during the 20th century.
As a county route, these sections of former U.S. Route 66 serve both local traffic and historical tourism. They often traverse diverse landscapes within San Bernardino County, from more urbanized areas to remote desert stretches, connecting communities and offering access to historic landmarks and attractions associated with the original highway. While not a single continuous route, County Route 66 refers to these distinct segments that trace the path of the iconic U.S. Route 66 through the county, often signed with both county route markers and "Historic Route 66" shields.