From Illinois State Highway 34 and Illinois Highway 146 intersection, take Illinois Route 146 eat 3 miles, turn left on Iron Furnace Road (County Road 12)
The Illinois Iron Furnace is the only remaining iron furnace structure in the state of Illinois. Iron was manufactured at the Illinois Furnace by the charcoal blast method. The furnace was built on a dry laid limestone foundation. The exterior of the furnace was manufactured of large limestone blocks quarried near the town of Cave-In-Rock. The interior wall, or lining, was constructed of firebrick from Pennsylvania. The space between the interior and exterior walls was filled with sandstone. Wrought iron binders were placed through the stonework and tightened to secure the walls. All of the stonework was dry laid. A 1/2 mile trail leading from the back of the picnic area features bottomland habitat and bottomland tree species. The trail winds along Big Creek and offers 2 or 3 deep old-fashioned fishing holes. Once a site of an iron making blast furnace, the picnic area contains a reconstructed blast furnace as a monument to our nation's past industry.