The road then descends and heads northwest, finally terminating at Interstate 5 at the foot of Mount Shasta at around 3,600 feet (1,100 m).

[citation needed] The highway continues north to Meyers, where it runs concurrently with US 50 into the city of South Lake Tahoe.

The road curves to the north through Tahoe National Forest before crossing into Nevada County and the town of Truckee.

[7] SR 89 runs concurrently with I-80 eastbound briefly before exiting to the north and continuing through Truckee and passing near Prosser Creek Reservoir outside of the town limits.

The segment through the park is typically closed during the winter due to very heavy snowfall and snowpack.

SR 89 briefly passes through the Klamath National Forest and Bartle and McCloud before coming to an interchange with I-5.

[5] One point of interest along California State Route 89 includes the Pony Express remount station in Woodfords, the Lake Tahoe Outlet Gates in Tahoe City (control of these gates was the source of the two-decade "Tahoe Water War" between lakeshore owners and downstream Truckee River water users), Plumas-Eureka State Park (containing Johnsville, a well-preserved '49er town, and Pioneer Ski Area, the first sport skiing area in the Western hemisphere), Lake Almanor and Lassen Volcanic National Park.

[16] Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage.