[1] It is 5.37 miles (8.64 km) long and runs in a northeast to southwest "L" pattern, entirely within Clackamas County.

It travels east and north as it ascends the slopes of Mount Hood, passing through several turns.

The highway splits into a pair of one-way roads around the parking lot of the Timberline Lodge ski area and ends at the namesake lodge.

[2][3][4] The Timberline Highway was opened on November 18, 1949, to serve the lodge and ski area alongside the Mt.

[5][6] It replaced an earlier road to the lodge from the west that was narrower and steeper.