Acorn Hill is a small dead end road off of Sam Day Hill in Phippsburg, ME. It is somewhat reminiscent of the Mowry Fire Tower road both because of its steepness (in parts) and because the terrain is very, very rough. Neither is as bad as Mowry, but you'll need your wits about you if you want to make it up without unclipping. And its steep enough in the middle section that you may want to have extra low gears. Also, you will probably need a cyclocross bike to make it up.
Acorn Hill Rd. is located in Maine. It is 209.1 meters long with an average gradient of 12.3% and a maximum gradient of 21.8%. Find similar hills.