Hi Ksusha,
The tick in your photo is an engorged female. The relatively long mouth parts and the dark plate on its back without white markings make me fairly certain it is a black-legged tick (an Ixodes species). If I had it in hand, I'd take a close look at a few other ID features to be 100% certain.

Black-legged ticks are the types of ticks that can transmit Lyme disease, but the latest data suggest that in Oregon the number of these ticks that carry the bacterium that causes Lyme disease is fairly low (3%-8% of the western black-legged ticks are carriers). They also typically need to be latched onto you for 24-48 hours to be able to transfer the bacterium to a person.

If you want a firmer ID on that tick, you could send it to us at the OSU Plant Clinic. Here is a link for instructions for how to submit a sample if you would like to do that...
https://bpp.oregonstate.edu/how-submit-insect-and-spider-materials

We cannot test ticks to see if they are carrying the bacterium that causes Lyme disease in our lab, but several other labs provide this service for a fee. Here is a link to information about that if you are interested...
https://web.uri.edu/tickencounter/testing/