*** Welcome to piglix ***

California State Route 175

State Route 175 marker

State Route 175
Map of western California with SR 175 highlighted in red
Route information
Defined by
Maintained by Caltrans
Length: 37.89 mi (60.98 km)
Restrictions: No vehicles more than 39 feet (12 m) in length between Hopland and Lakeport
Major junctions
West end: US 101 at Hopland
  SR 29 near Lakeport
East end: SR 29 at Middletown
Highway system
SR 174 SR 177

State Route 175 marker

State Route 175 is a state highway in California, United States, connecting Hopland in Mendocino County and Middletown in Lake County

CA Route 175 connects U.S. Route 101 at Hopland to State Route 29 near Lakeport through the Mayacamas Mountains. From there it joins Route 29 until Kelseyville, where it loops out until meeting Route 29 again at its end at Middletown. The section between Hopland and Lakeport is also known locally as the "Hopland Grade", or "Hopland Pass."

Originally constructed in the early 1920s, it is one of the steepest and most difficult to drive of any California state highway. Indeed, until recently it was called the "crookedest road in California". Vehicles more than 39 feet (12 m) in length are banned from the Hopland Grade, due to its many tight hairpin turns and curves.

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 an overlap due to a correction or change, and T indicates postmiles classified as temporary (for a full list of prefixes, see the list of postmile definitions). 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.


...
Wikipedia

...