Washington State Route 123

State Route 123
SR 123 is highlighted in red.
Route information
Auxiliary route of US 12
Maintained by WSDOT
Length	16.34 mi[1] (26.30 km)
Existed	1967[2]–present
Major junctions
South end	US 12 in Gifford Pinchot NF
North end	SR 410 in Mt. Rainier NP
Location
Country	United States
State	Washington
Highway system
State highways in Washington Interstate US State Scenic Pre-1964 1964 renumbering Former
← SR 122 → SR 124

State Route 123 (SR 123) is a state highway in the Gifford Pinchot National Forest and Mount Rainier National Park east of Mount Rainier in the U.S. state of Washington. Located in the counties of Lewis and Pierce, the 16.34-mile (26.30 km) long roadway extends through a heavily forested canyon from U.S. Route 12 (US 12) to SR 410. First established as a branch of State Road 5 in 1923, the designation of SR 123 has changed from a branch of Primary State Highway 5 (PSH 5) in 1937 to SR 143 during the 1964 highway renumbering and SR 123 in 1967. The northern terminus of the highway, Cayuse Pass, is closed annually and in late 2006, the Hanukkah Eve windstorm of 2006 washed out a 10.90-mile (17.54 km) long segment of the roadway.