Oregon Route 293 is an east-west highway despite having an odd number.

There is speculation that Oregon Route 293 signs were posted in error, as OR 293 has always been the internal highway number used by the Oregon Department of Transportation (ODOT).

However, in 2002, ODOT revised its policy to allow for the signage of otherwise unnumbered state highways, resulting in the official establishment of Oregon Route 293.

On October 10, 1963, there was agreement with the Oregon State Highway Commission and Wasco County to turn the Wasco County section of the Antelope Highway into a state-maintained road.

The section in Jefferson County was turned into a state-maintained road on September 8, 1971.