 State Route 243 ( SR 243 ) , or the Banning @-@ Idyllwild <unk> Highway , is a 30 @-@ mile ( 50 kilometer ) two @-@ lane highway that runs from Banning , California ( in the north ) to Idyllwild , California ( in the south ) in Riverside County , California . The highway is a connector between Interstate 10 ( I @-@ 10 ) and SR 74 . Along its route , it provides access to the San <unk> National Forest . A road from Banning to Idyllwild was planned around the turn of the twentieth century , and was open by 1910 . The road was added to the state highway system in 1970 . 
