What is now OR 242 was a wagon route over the Cascade Range. It was built in 1862. The highway for automobiles was constructed in 1924. In the original plan for the U.S. Numbered Highway plan on November 11, 1926, U.S. Route 28 (US 28) was designated from Florence to Ontario. US 28 followed the alignment of OR 242. The American Association of State Highway Officials approved to change US 28 between Eugene and Prineville to US 126 in 1951. In 1962, the Clear Lake Cutoff was completed. The completion resulted in US 126 being rerouted from McKenzie Pass to the cutoff. The rerouting included a concurrency with US 20. After the rerouting, the OR 242 designation was formed on the McKenzie Pass route. In February 2011, OR 242 was added to the National Register of Historic Places. In September 2011, McKenzie Pass was designated as an Oregon Scenic Bikeway