Washington State Route 123

State Route 123
SR 123 is highlighted in red.
Route information
Defined by RCW 47.17.230
Maintained by WSDOT
Length:	16.34 mi (26.30 km)
Existed:	1967 – present
Major junctions
South end:	US 12 in Gifford Pinchot NF
North end:	SR 410 in Mt. Rainier NP
Highway system
State highways in Washington Interstate US State Scenic Former PSH 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.

State Route 123 (SR 123) begins at an intersection with U.S. Route 12 (US 12) northeast of Packwood, in the Gifford Pinchot National Forest. Paralleling US 12 and the Ohanapecosh River, the highway crosses Boulder Creek and enters a canyon where the roadway encounters Forest Route 44 (FR 44), a connector from SR 706 to Mount Rainier National Park. The segment of SR 123 in the heavily forested canyon is the busiest along the road, with a daily average of 803 motorists in 2007. Still in the canyon, the roadway exits the Gifford Pinchot National Forest and enters the Mount Rainier National Park. The roadway enters Pierce County from Lewis County and passes the Ohanapecosh Visitor Center, located 1,900 feet (579.12 m) above sea level. SR 123 crosses Laughingwater Creek and passes Silver Falls and the entrance to Steve Canyon to the trailhead of the Grove of the Patriarchs Trail. Now following the Chinook Creek, the highway travels into a tunnel under Seymour Peak and ends at an intersection with SR 410 at Cayuse Pass.