Unknown Road in W Corwall is located in Connecticut. It is 1410.5 meters long with an average gradient of 14.5% and a maximum gradient of 27.5%. Find similar hills.
In the "meanest mile" competition for Connecticut, this hill probably wins. Unfortunately it isn't a public road, but some rich person's driveway (you can see a single house at the top with a rather large outdoor pool). There's an electronically controlled gate at the bottom, which was open the only time I checked it out. I decided not to attempt climbing it however.