ORS § 201.050
The boundary of Columbia County is as follows: Beginning at the point where the northern boundary of the state is intersected by the projection north of the range line between ranges 5 and 6 west of the Willamette Meridian; thence south along such projection and range line to the southwest corner of township 4 north, range 5 west; thence east along the line between townships 3 north and 4 north of the Willamette Base Line to the northeast corner of section 3, township 3 north, range 3 west; thence south along section lines to the southwest corner of section 11 of such township; thence east along section lines to the southeast corner of section 12 of such township; thence south along the township line to the southeast corner of section 13 in such township; thence east along section lines to the northeast corner of section 21, township 3 north, range 2 west; thence south to the southeast corner of section 21 of such township; thence east along section lines to the southwest corner of section 23, township 3 north, range 1 west; thence north to the west quarter-corner of such section; thence east along quarter-section lines to the boundary of the state; thence northerly and westerly along the boundary of the state to the point of beginning.
ORS 201.050