Matthiessen State Park near Oglesby, Illinois, developed from the 176-acre Deer Park estate of Frederick William Matthiessen into a protected area of 1,938 acres. After his death in 1918, his heirs gave the land to the state, and it was renamed for him in 1943. The estate’s buildings eventually vanished, though concrete stairs into the canyon remain. The park is especially known for dells and ravines carved by water flowing from Matthiessen Lake to the Vermilion River, forming sandstone canyons and falls. Its cool canyon floors, bluff-top woodlands, and mineral-rich springs support distinctive plant life and wildlife, while trails make the scenery accessible for recreation.