Dorothy Pecaut Nature Center in the 1,089 acre Stone State Park in the northwest corner of Sioux City. Primarily woodlands along with some grasslands set in the beautiful Loess Hills. 14000 sq ft nature center Start Point: I-29 Exit 151. From Exit 151 proceed NORTH on IA12-S (a.k.a. Riverside Blvd). Proceed 3.5 mi on IA 12-S. Nature Center entry will be on your right (EAST) Woodlands, Oak Savannah, some grasslands. Excellent birding year-round. Migration can be exceptional.