In Oregon, the state Constitution (Article IV, Section 6) and several statutes (primarily ORS 188.010) govern the process for redistricting. The constitution specifies that redistricting of the 60 seats in the Oregon House of Representatives and the 30 seats in the Oregon Senate shall be performed at least every ten years in the odd year after census, and designates the Legislature as the responsible entity.

As a practical matter, the Legislature also conducts redistricting for Oregon’s five United States congressional representatives, even though there is no express provision in the Oregon or federal constitutions on how congressional redistricting should be done.

The criteria the legislature uses are set by ORS 188.010 which states that:

  1. Each district, as nearly as practicable, shall:
    1. Be contiguous;
    2. Be of equal population;
    3. Utilize existing geographic or political boundaries;
    4. Not divide communities of common interest; and
    5. Be connected by transportation links.
  2. No district shall be drawn for the purpose of favoring any political party, incumbent legislator or other person.
  3. No district shall be drawn for the purpose of diluting the voting strength of any language or ethnic minority group.
  4. Two state House of Representative districts shall be wholly included within a single state senatorial district.

The redistricting plans take the form of legislation which is forwarded to the governor for approval or veto. The state constitution specifies that the Legislature must finish its work on Oregon legislative redistricting by July 1 of the year following the census. If lawmakers fail to pass a redistricting plan or if the plan is vetoed by the governor and the veto is not overridden by the Legislature, the task falls to the Secretary of State.