Portland, down I-5 to Medford, and Bend
Portland's own listings are mostly game stores, and a couple of them sell Japanese cards. Most of the area's sports-card shops are in the suburbs, on the west side around Beaverton and Hillsboro and south in Oregon City.
Down I-5, Salem, Eugene and Medford each have shops close together downtown, and in Eugene and Medford you can walk between several of them.
Bend, about three hours from Portland over the Cascades, has shops along the US-97 corridor. Many Oregon listings mention graded cards.
Card shows, conventions, and tournaments happening across Oregon.