Welcome to Phelps Mill Park. Walk across the dam via the historic pedestrian bridge and check out the water flow from various angles. If the place is busy, you might also catch people jumping off the bridge and swimming.
When the historic Mill building is open, you are able to explore it, as well as watch a video about the history.
Because of all the possible muggles, this cache is a little off the beaten path. But as geocachers, we are all used to a little effort to gain our smileys, aren't we?