SR 189 begins at Lake Gregory Drive approximately twenty feet north of State Route 18, between the community of Arrowhead Highlands to the west and the community of Rimforest to the east. It wends its way northeastward to the community of Twin Peaks. It continues roughly eastward through Twin Peaks to the community of Agua Fria (Spanish, cold water), where it forms a tee with the northern terminus of Daley Canyon Road. It turns northeast and continues from there through the downtown section of the community of Blue Jay. It ends at State Route 173 in the Village area of the community of Lake Arrowhead.
In 1933, a road from Strawberry Peak to the road between Cajon Pass and Lake Arrowhead was added to the state highway system.[4] It was given the number of Route 189 in 1935.[5] The route was unchanged by the 1964 state highway renumbering.[6]
Major intersections
Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage. R reflects a realignment in the route since then, M indicates a second realignment, L refers to an overlap due to a correction or change, and T indicates postmiles classified as temporary (for a full list of prefixes, see California postmile § Official postmile definitions).[1] Segments that remain unconstructed or have been relinquished to local control may be omitted. The entire route is in San Bernardino County.
^ abcCalifornia Department of Transportation. "State Truck Route List". Sacramento: California Department of Transportation. Archived from the original(XLS file) on September 5, 2015. Retrieved June 30, 2015.
^Federal Highway Administration (March 25, 2015). National Highway System: California (South)(PDF) (Map). Scale not given. Washington, DC: Federal Highway Administration. Retrieved September 16, 2017.
^Natzke, Stefan; Neathery, Mike & Adderly, Kevin (June 20, 2012). "What is the National Highway System?". National Highway System. Washington, DC: Federal Highway Administration. Retrieved July 1, 2012.
^California State Assembly. "An act...relating to State highways". Fifty-first Session of the Legislature. Statutes of California. State of California. Ch. 274.
