From the blog:
"A friend told me that Bolton Notch was “almost as steep as Lincoln Gap” and at first I just assumed that this was the usual “my driveway is the steepest hill on the planet” hyperbole you find all over the internet. Turns out he’s not far off. The first 1 KM averages almost 17%! It’s quite similar to Mount Tom. There are two immense walls of 20%, punctuated by a couple spots to recover, if only slightly. There are also some dirt/gravel sections [now paved] to contend with. What makes it easier than Mount Tom, is that Mount Tom’s sections of 20+% are both longer, and happen a bit later in the hill. The first section on Bolton Notch is sprintable, and you can get up it with a little determination. After the short recovery section, the next section on Bolton Notch is really, really, nasty, but once you get to the top of that, you’re done with the really evil stuff and you can roll it up to the top. On Mount Tom, just as you finish one huge slog, you’re hit with another one just as bad, and that second one is much more demoralizing."
Bolton Notch is located in Vermont. It is 2190.7 meters long with an average gradient of 11.2% and a maximum gradient of 27.9%. Find similar hills.