Oregon Revised Statutes Education and Culture § 335.490

(1) Except as otherwise provided in subsection (2) of this section, any union high school district may, when authorized by the electors of the district, extend the course of study in the district to include five years above the seventh grade or six years above the sixth grade, and in like descending order may extend its course to include kindergarten or any or all grades of the schools in the union high school district in the manner provided in ORS 335.495 to 335.505. The decision to vote the course of study down to include kindergarten shall include, upon request of district electors or the district school board, a decision on whether, in the case of a board consisting of five members, the number of members of the board shall be increased to seven members.

(2) No union high school district shall extend the course of study in the union high school district unless such course of study is extended to include kindergarten and grades 1 through 12, of the schools in the union high school district.

(3) When a union high school district extends the course of study, the extension applies to all component school districts lying wholly within the union high school district.