Oregon Constitution Art. XVIII § 11

Until otherwise provided by law, the judicial districts of the State, shall be constituted as follows: The counties of Jackson, Josephine, and Douglas, shall constitute the first district. The counties of Umpqua, Coos, Curry, Lane, and Benton, shall constitute the second district.--The counties of Linn, Marion, Polk, Yamhill and Washington, shall constitute the third district.--The counties of Clackamas, Multnomah, Wasco, Columbia, Clatsop, and Tillamook, shall constitute the fourth district--and the County of Tillamook shall be attached to the county of Clatsop for judicial purposes.