Oregon Revised Statutes Public Financial Administration § 294.080

(1) Except as provided in subsections (2) and (3) of this section, the county treasurer shall credit to the general fund of the county all interest received from any investment made from the general cash balance of any funds in the hands of the county treasurer. If the entire investment is made from a specific fund, however, the treasurer shall credit the interest to the fund from which the investment was made.

(2) The county fiscal officer of a community college district, as defined in ORS 341.005, shall credit to the general fund of the district all interest received from any investment made by funds in the hands of the county fiscal officer. If the entire investment is made from a specific fund, however, the county fiscal officer shall credit the interest to the fund from which the investment was made.

(3) Interest earned by investment of any moneys received by the county treasurer from any source, which moneys have been designated for a particular municipal corporation as defined in ORS 294.311, shall be credited to the account of the particular municipal corporation and not to any county fund.