According to the Wisconsin DNS website, the 32,000 acre Horicon Marsh is the largest freshwater cattail marsh in the United States. About a third of this is owned by the state of Wisconsin. There are hiking trails, viewing locations and roads of varying quality throughout. The marsh is a mecca for birdwatchers, who come to see the 300+ species that live there. The easiest “trail” is the Horicon “TernPike” Auto Tour, which can be driven. There are also a few really nice trails in this area, with board walks over some of the marsh. Other trails and overlooks are spread throughout the marsh. Do check their website to know when access roads are open. Many are  partially closed for a large part of the year, leaving you to make a tight turnaround at a gate and a long trip back! Beyond the auto tour road, most trails are really not ideal for anyone other than hikers.

Horicon Marsh Visitors Center
N7725 Highway 28
Horican, WI 53032