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 Roundrop 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.