Canton Ave is located in Pennsylvania. It is 141.1 meters long with an average gradient of 11.1% and a maximum gradient of 26.1%. Find similar hills.
Hill number 9 in the annual Pittsburgh Dirty Dozen. This is one of the many claimants to the title Steepest Hill in the World, but its claim is, in my opinion, based on faulty data. I've seen it listed as 35% average gradient with a maximum of 37%. The RWGPS data, as you can see, does not support that claim. On its own, that doesn't mean anything—it could easily be bad data; but I have been there with a gradometer app, and was only able to find a maximum gradient of about 21 or so. And more importantly, it doesn't look like 30+%, the map here feels about right to me. The cobblestones, of course, make it much harder than it would be as smooth pavement.