This has to be the crown jewel of Waukesha County parks. There are numerous amenities I'll list later. The park is very well maintained and staffed appropriately. They recently added a Beer Garden, open Wed-Sun, with snack bar food and often a food truck. There is also a path around the lake that's about a mile long.
The lake is a former quarry, so is very deep. The park is also attached to the large Bugline Trail.
Amenities at Menomonee Park include many camp sites, both individual and group; a beach with swimming; archery; scuba; fishing; many picnic areas with grills; hiking; kayaking; beer garden; snack bar; and dog exercise and beach areas.
Almost afraid to post this as I don't it attracting more people 😜.