This kind of sighting is exactly what drew me into all this in the first place. The fact that it was hovering and stationary over the tree line is the detail I'd focus on - conventional aircraft don't just sit there, and drones have a fairly recognisable sound and movement pattern.
I'm in the Pacific Northwest myself and we get a lot of unusual reports from this region. What I've been reading lately suggests certain geographical features - ridge lines, water sources, that sort of thing - seem to attract these observations repeatedly over decades. Not claiming to know why, just that the pattern is there.
Would really help to know a few things. Roughly what direction were you facing, and did it make any sound at all? Also how long did it hover before it moved or disappeared? The duration is something a lot of people forget to mention but it matters quite a bit when trying to rule things out. Hoping others who've seen similar will chime in here because the more accounts we can compare the better picture we start to build.