Oregon 4 is in the southwestern part of the state. Its area is relatively large but still smaller than Oregon 2; therefore, it is fairly rural and does not have major cities. The race makeup is 90.1% white, 2.2% Asian, and 1.7% Native American.

Peter DeFazio (D) has been congressman since 1986. In 2016, he won by a margin of 15.8% against Art Robinson (R). In 2014, he won by a margin of 21% against Art Robinson as well. The rivalry continues this year.