A lot of older neighborhoods in Portland have rings for tying up horses along the edges of the street. We have one in front of our house which was built in the early 1920's. I found myself wondering who was using horses for transportation then. Was milk being delivered in horse drawn wagons? I didn't find the answer to that but I did find this interesting bit of history about Portland streetcars.
And here is something about early dairies in Portland with photos...