After many decades of work the city of Portland has manage to get a trails system in along the part of the Willamette River that runs through Portland. Through a series of different trails you can make a long loop going from above the Steel Bridge down to the Sellwood Bridge and back. The trail includes sections that runs through parks, neighborhood streets, East Bank Esplanade and official trails. One can do this loop as a half marathon walk or run but it makes for an easier, more pleasant bike Ride.
This is for the West side of the Willamette River.
The middle section goes through Tom McCall Waterfront Park.