Once in Mankato Minnesota, find Riverfront Drive, go north and once you pass the intersection of Madison & Riverfront 3rd avenue is your next left, take it. The name of the quarry is The Southern Minnesota Construction (SMC) Rock Quarry. You go out a few miles until you get to a rock quarry and a cemetery both on your left. Turn into the dirt road directly before the cemetery. To your left will be a rock quarry with some fairly deep water in it (10-15 feet or so- enough to jump, NOT enough to dive) There are a couple of jumping spots, the one I tried (which worked beautifully) was a very short path (the cliff is very close to the road) with a large rock next to it. Jump away.