 State Route 7 ( SR 7 ) begins at an intersection with U.S. Route 12 ( US 12 ) , a major east – west highway , in Morton . Traveling north as Second Street and paralleling the Morton – Tacoma ( Mountain Division ) route of Tacoma Rail , the street intersects Main Avenue , which continues west out of the city as SR 508 . After leaving Morton , the highway becomes the Mountain Highway and passes through a heavily forested canyon near Mount Rainier and parallel to the Tilton River and <unk> Creek . Bridging the Nisqually River , the highway leaves Lewis County and enters Pierce County . In Elbe , the roadway intersects SR 706 , which goes east to Mount Rainier National Park . Following the Nisqually River , which has become Alder Lake , and Tacoma Rail line , SR 161 branches off towards Eatonville and SR 702 travels west from the plains to McKenna . 
