Join the Grundy County Historical Society for a Walk-a-Thon! Historical Anecdotes Beautiful Historic Site Photo Ops Photo Contest $30 registration fee (includes shirt). Register at (815) 942-4880, [email protected], or at The Grundy County Historical Society. You must register prior to September 19 for a shirt.  

The Tully Monster is the State Fossil for Illinois. It was found in the Mazon Creek and only exists in Grundy County. Learn about the Tully Monster. See Tully Monster fossils. Participate in a Scavenger Hun and play games.