Opened in April of 2011, this area has 229 acres adjacent to the 27 acre Lake in the Hills Fen State Nature Preserve. Over 400 species of plants, 80 species of birds, 40 species of butterflies, and a myriad of other animals depend on this preserve for a place to live. There are only 26 acres of hanging fens in the nation and the Lake in the Hills Fen has approximately four of them.
The Fen is located between Pyott Road on the east and Jefferson Street on the west. There are two entrances and parking areas. On the east side use Barbara Key Park, which is on Pyott Road. Enter the west side through the McHenry County Conservation District Park on Jefferson.