Natural areas are open from 6am to 11pm daily.
Big Marsh is the largest wetland complex in the Calumet Region. A water control structure was installed in 2015 to control water levels and establish hemi-marsh conditions. The water control structure, along with removal of invasive species, has resulted in the reemergence of the bird population at Big Marsh. Birds are coming back in abundance, including a pair of yellow headed blackbirds, a species which has not been observed at Big Marsh for more than twenty years.