Oregon's 3rd congressional district covers most of Multnomah County, including Gresham, Troutdale, and most of Portland east of the Willamette River. It also includes the northeastern part of Clackamas County and all of Hood River County. Generally, most of Portland east of the Willamette River is in the 3rd District.

The Democratic Party of Oregon is the Oregon affiliate of the Democratic Party. The State Central Committee, made up of two delegates elected from each of Oregon's 36 counties and one additional delegate for every 15,000 registered Democrats, is the main authoritative body of the party. The party has 17 special group caucuses which also each have representation on the State Central Committee.