Wikipedia https://en.wikipedia.org/wiki/Matthiessen_State_Park
Official Website https://www.dnr.illinois.gov/Parks/Pages/Matthiessen.aspx
More information http://www.stateparks.com/matthiessen.html
Address 15-2519 Matthiessen Ln, Oglesby, IL 61348, USA
Coordinates 41°17'46.061" N -89°1'30.81" E