ORS 36.725: Venue.

A petition pursuant to ORS 36.615 must be made in the court for the county in which the agreement to arbitrate specifies the arbitration hearing is to be held or, if the hearing has been held, in the court for the county in which it was held. Otherwise, the petition may be made in the court for any county in which an adverse party resides or has a place of business or, if no adverse party has a residence or place of business in this state, in the court of any county in this state. All subsequent petitions must be made in the court hearing the initial petition unless the court otherwise directs.