For all that Eugene, and Lane County, is often thought of simply as a Democratic stronghold, the reality is more complicated. It is true that in major races, the weight of the county's vote ordinarily goes Democratic, often by a large percentage. But more locally, contests are often more competitive, especially when party labels are not visible (as for nonpartisan local government offices).
So the effort to redraw the Lane County Commission districts, five of them, becomes a complex undertaking. Based on party registration and typical voting patterns, you might expect three Democratic-leaning districts, and two Republican-leaning. But that conclusion isn't foregone, since a large part of the Democratic vote is concentrated in the University of Oregon district and in south Eugene, and near the downtown area. Much of the rest of Eugene, and most of Springfield, ranges from gently Democratic to simply competitive, to increasingly Republican in the landscape becomes more rural.
With all that in mind, take a look at the commission redistricting maps the Eugene Register-Guard has posted. Note that some plans (like scenario 2) have three compact districts, and a couple of large rural ones. And that others, like scenario 6, have more puffed-out center districts that reach more into the rural area. Which do you think might be endorsed by each party?
The R-G story notes that "Board members have said there’s no place for politics in the process." Good luck with that.