State Highways, including Highways 1, 12, 37, 101, 116, 121, and 128 are part of an interconnected state highway system, built and maintained by the California Department of Transportation (Caltrans). The Sonoma County Department of Transportation and Public Works has no jurisdiction over the California State Highway System.
The County, or Unincorporated, Road System makes up the majority of roads within Sonoma County. This includes most roads that are (a) publically-owned, (b) publically-accessible, (c) outside of city limits, and (d) not part of the State Highway System. These are owned and maintained by the Sonoma County Department of Transportation and Public Works.
Public roads belong to the city if they are within city limits and not part of the State Highway System. The Sonoma County Department of Transportation and Public Works has NO jurisdiction over city streets.
Private & Other Streets
Some roads may be privately-owned or administered by other agencies. Roads often fall under this category if they are inside any of the following areas: public parks, gated and/or private communities, farms, ranches, wineries, military installations, schools and/or universities.