The highway was part of the Tacoma - Mount Rainier branch of Primary State Highway 5 (PSH 5 TR) from 1937 until 1964 and ran from Tacoma south to Elbe and east to Longmire. In 1964, PSH 5 TR from Tacoma to Elbe became part of SR 7 and the Elbe to Mount Rainier section became SR 706.