My wife Adele and I live in Sellwood right next to the route of the Portland Marathon, in two directions. Technically for a period we will be "Land-Locked" with the race locking us in between 19th and 21st. Volunteers will be stationed at intersections to allow cars through when runners are not present. It's always a great time to stand along the course and cheer them on. Here is the course map and more info for you.