red granite quarry is 2 hours away from madison and is pretty fun, but the biggest cliff there is only like 20 feet. but the tops of all the cliffs are flat since it used to be a quarry so its easy to get a running start and throw gainers and stuff. Also since it was a quarry there isn't anything hidden under water that you need to watch out for, the cliffs drop straight down mostly except for a few spots where you need to jump out only like 5 feet max.
I think there is a spot on Mendota too. There is also an old quarry down by racine that you can jump.
The biggest spot I know of is in the dells. it's on private property though. I measured it at 35 feet.