The State Scenic Highway System is a list of highways, mainly state highways, that have been designated by the California Department of Transportation (Caltrans) as scenic highways. The California State Legislature, primarily through , makes highways eligible for designation as a scenic highway. For a highway to be declared scenic, the government with jurisdiction over abutting land must adopt a "scenic corridor protection program" that limits development, outdoor advertising, and earthmoving, and Caltrans must agree that it meets the criteria. The desire to create such a designation has at times been in conflict with the property rights of abutters, for example on State Route 174. Scenic highways are marked by the state flower, a California poppy, inside a rectangle (for state-maintained highways) or pentagon (for county highways).