A state highway, state road, or state route is usually a road that is either numbered or maintained by a sub-national state or province. A road numbered by a state or province falls below numbered national highways in the hierarchy.

A route number, designation or abbreviation is an identifying numeric designation assigned by a highway authority to a particular stretch of roadway to distinguish it from other routes and, in many cases, also to indicate its classification, general geographical location and/or orientation. The numbers chosen may be used solely for internal administrative purposes; however, in most cases they are also displayed on roadside signage and indicated on maps.