The western terminus is at US 101 in eastern Carpinteria. It climbs above the Pacific Ocean to reach the mountains west of Lake Casitas. The portion of the road between US 101 and Lake Casitas is called Casitas Pass Road, and the portion between Lake Casitas and Ojai is called Baldwin Road. However, this part of the road is rural and is not used as a primary thoroughfare. SR 33 is recommended to reach Ojai from U.S. 101. SR 150 joins SR 33 (Maricopa Highway) near Meiners Oaks and remains co-signed with the route into the Ojai city limits, where it is known as Ojai Avenue. It runs southeast on Ojai-Santa Paula Road and serves as the major connector between the cities of Ojai and Santa Paula, running past Thomas Aquinas College. In Santa Paula, it becomes 10th Street and ends at an interchange with SR 126.
The other names of Route 150 include Rincon Road (starts at U.S. Route 101 and ends at State Route 192), Casitas Pass Road (starts at Route 192 and ends at Santa Ana Road near Lake Casitas), Baldwin Road (starts at Santa Ana Road and ends at the south junction with Route 33), Ventura Avenue (co-signed with Route 33), Ojai Avenue (starts at the north junction with Route 33 and ends at Reeves Road, approximately one mile east of the east limit of Ojai), Santa Paula/Ojai Road (starts at Reeves Road and ends at the north limit of the City of Santa Paula), Ojai Road (starts at the north limit of Santa Paula and ends at Santa Paula Street in Santa Paula) and 10th Street (starts on Santa Paula Street in Santa Paula and ends at Route 126).
The route was opened in 1897. Before the construction of US 101, it was part of the main highway between Los Angeles and Santa Barbara. Originally, State Route 150 followed the alignment of State Route 192 through the Santa Barbara foothills and climbed up San Marcos Pass via the present-day route of State Route 154 before heading west on State Route 246, passing through Santa Ynez, Solvang, and Buellton and ending in Lompoc at State Route 1 (Cabrillo Highway). The only current remnants of that routing are at the mileage signs for westbound State Route 150, which have the control city as Santa Barbara west of Santa Paula, even though SR 150 currently ends 12 miles (19 km) east of the city.
A portion of the route between Santa Paula and Ojai was closed indefinitely by a landslide in February 2024 following a significant rain storm.[6][7] Cleanup and the reopening of the section from Stonegate Road in Santa Paula to Steckel Park, north of the city, was delayed due to the risk of triggering additional slides that could damage nearby homes or utility lines.[8]
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 numbers reset at county lines; the start and end postmiles in each county are given in the county column.
^ 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: Oxnard, CA(PDF) (Map). Scale not given. Washington, DC: Federal Highway Administration. Retrieved September 24, 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.