Due to a technicality, Cavanal Hill (in Oklahoma of all places) claims to be the tallest hill in the world. At 1999 feet, if it was a foot taller, it would classify as a mountain. Hence the tallest hill. Seems to be a favorite hill for local cyclists.
Cavanal Hill is located in Oklahoma. It is 7480.6 meters long with an average gradient of 7.2% and a maximum gradient of 13%. Find similar hills.