In the California Route Marker Program, which designates county routes in California, only two highways exist in the "R" zone: CR R2 and CR R3. Both of these routes are in Riverside County.

County Route R2 is also known as Kaiser Road. Its southern end is SR 177 and its north end is at Eagle Mountain, a modern day ghost town.

The route was defined in 1964, and has not been altered since then.

County Route R3 is also known by several other names along its route. Portions of the highway are called Sage Road, Cactus Valley Road, and State Street. Its southern end is SR 79 and its north end is SR 74.

At its north end in Hemet, it provides a major transportation route.

Historic information conflicts as to the date the route was defined. Some information indicates the highway was created in 1966, although other sources give a commissioning date of 1973.