Oregon Revised Statutes Counties and County Officers § 201.030

(1) The territory bounded north by Multnomah County, east and south by the Willamette River and west by the meridian line, and that part of Washington County lying in section 12, in township 3 south of the base line, and township 1 west of the Willamette Meridian.

(2) So much of Yamhill County as is embraced within township 3 south of range 1 west of Willamette Meridian, as described on the government surveys.

(3) The boundary line between Clackamas and Marion Counties commences in the center of the Willamette River where the first section line of the government surveys below the town of Butteville in Marion County intersects the Willamette River; thence east to the third section corner from such river; thence south to the township line; thence in a due east course to the middle of Pudding River; thence up such river to the mouth of Butte Creek; thence up Butte Creek to a point at its source, from which point a rock 7 by 4 by 3 feet above ground marked “X” B. S. bears north 85 degrees east twenty-two one-hundredths chains, and from which point another rock 4 by 3 by 3 feet above ground marked “X” B. S. bears west thirty-five one-hundredths chains, which point is eighteen and forty one-hundredths chains south and fourteen and seventy-five one-hundredths chains west of the quarter-section corner between sections 11 and 12 in township 8 south, range 3 east of the Willamette Meridian; thence due east to the summit of the Cascade Mountains.