Mina Sauk Falls is the highest waterfall in the state of Missouri, on the slopes of Taum Sauk Falls, the highest point in the state of Missouri, overlooking the deepest valley in the state of Missouri.
Despite all that, they aren't all that impressive. But, in fairness, this is only part of the highest reach, and the (frozen) water level was fairly low in January 2008.
It's on a pleasant, 2.6 mile loop trail with good views of the Ozarks. Don't skip the loop when you collect the high point.