Oregon Revised Statutes Elections § 247.015

(1) A qualified person absent from the state may register by mailing to the county clerk for the county in which the person resides a completed registration card or a signed statement containing the information required on a registration card.

(2) On written request from a qualified person who by physical incapacity cannot register in the office of the county clerk, the county clerk of the county in which the person resides shall send the person a registration card or register the person at the person's residence.

(3) An otherwise qualified person who will become a United States citizen after the 21st calendar day immediately preceding an election may register before the 20th day before the election. The county clerk of the county in which the person resides shall cancel the person's registration before the election unless the person appears before the county clerk and provides evidence of citizenship.