OR Rev Stat § 255.165 (2021)
2021 Oregon Revised Statutes|Volume : 06 - Local Government, Public Employees, Elections|Chapter 255 - Special District Elections|Section 255.165 - Signature requirements.

(1) Except for a district measure of the Port of Portland, a metropolitan service district organized under ORS chapter 268, a school district with an enrollment exceeding 40,000 pupils or a mass transit district situated in a metropolitan statistical area with a population exceeding 400,000, other than a mass transit district measure relating to a route, schedule or fare change, a petition to refer or initiate a district measure must be signed by a number of electors registered in the district that: (a) For an initiative petition, is not less than 15 percent of the total number of votes cast in the district for all candidates for Governor at the most recent election at which a candidate for Governor was elected to a full term; and (b) For a referendum petition, is not less than 10 percent of the total number of votes cast in the district for all candidates for Governor at the most recent election at which a candidate for Governor was elected to a full term. (2) A petition to refer or initiate a district measure of the Port of Portland, a metropolitan service district organized under ORS chapter 268, a school district with an enrollment exceeding 40,000 pupils or a mass transit district situated in a metropolitan statistical area with a population exceeding 400,000, other than a mass transit district measure relating to a route, schedule or fare change, must be signed by a number of electors registered in the district that: (a) For an initiative petition, is not less than six percent of the total number of votes cast in the district for all candidates for Governor at the most recent election at which a candidate for Governor was elected to a full term; and (b) For a referendum petition, is not less than four percent of the total number of votes cast in the district for all candidates for Governor at the most recent election at which a candidate for Governor was elected to a full term. (3) Except for a district measure of the Port of Portland, a metropolitan service district organized under ORS chapter 268, a school district with an enrollment exceeding 40,000 pupils or a mass transit district situated in a metropolitan statistical area with a population exceeding 400,000, other than a mass transit district measure relating to a route, schedule or fare change, a petition to refer a district measure must be filed with the elections officer not later than the 30th day after adoption of the district ordinance sought to be referred. (4) A petition to refer a district measure of the Port of Portland, a metropolitan service district organized under ORS chapter 268, a school district with an enrollment exceeding 40,000 pupils or a mass transit district situated in a metropolitan statistical area with a population exceeding 400,000, other than a mass transit district measure relating to a route, schedule or fare change, must be filed with the elections officer not later than the 90th day after adoption of the district ordinance sought to be referred. [1979 c.190 §295; 1983 c.350 §75; 1987 c.211 §1; 1989 c.328 §1; 2009 c.11 §24]