Avoca Mounds
(Avoca Lake Group)
  The Avoca Lake Mound Group is located in Lakeside Park in the village of Avoca on the shore of Avoca Lake, a backwater slough of the Wisconsin River. This group presently has six linear and four conical mounds, but possibly had more mounds in the past.
  Unfortunately, the mounds are smack in the middle of the busy community park and campground, scattered between playground, shelters, picnic tables etc. There is a lot of foot traffic going over these mounds. To add insult to injury, the site gets motor-mowed with the rest of the park territory.
If you know what those white objects on top of conical mounds are, please let me know.
According to Iowa County Cultural Resources page, there should be another three mounds preserved around Avoca at undisclosed locations.