From the DuPage County (IL) Guide, published 1939, p. 216:
Near Deer Park, a county forest preserve actually inhabited by a few deer.Just beyond the entrance, facing Church Road, two old grinding stones form a MONUMENT TO AN EARLY LINSEED OIL MILL, which formerly stood a short distance to the east. Perhaps the first such mill in Illinois, it was started in 1847 by John Henry Franzen, a German immigrant of 1836. Frederick Korthauer, a German cabinetmaker and painter who settled near the Franzens about 1840, built the mill for them and shared in its management. After hauling their flaxseed to the mill, the farmers used to gather in Franzen's house for a "hot-stove session," a good dinner, and a night's lodging.In 1870, coincident with the general shift in this region from wheat and flax crops to corn, the mill ceased functioning.