DeKalb County was formed on March 4, 1837, out of Kane County, Illinois. The county was named in honor of Johann de Kalb, a German (Bavarian) hero of the American Revolutionary War. DeKalb County is approximately 632.7 square miles and is located 63 miles west of Chicago. There are 19 townships in the county, with the county seat at Sycamore.
Starting in 1834 settlers began to make their homes in DeKalb County along the streams and wooded areas because of the fertile soil, hunting, and food and water suppplies. Major growth stemmed from the introduction of the railroad, which brought easier methods of transportation and opportunities for business growth. Some of the notable industries based in DeKalb County include: Sandwich Manufacturing Company, Marsh Harvester Company, Barbed Wire, Gurler Brothers Pure Milk, DeKalb AgResearch, Inc., and many more.
The county has always been noted for agriculture. In 1852 the first Agricultural Fair was held in Sycamore under the supervision of the DeKalb Agricultural Society. Eventually farmers, businessmen, bankers, and newspapermen organized to become the DeKalb County Soil Improvement Association. In later years the DeKalb County Soil Improvement Association would split into two entities, becoming the DeKalb County Farm Bureau and the DeKalb Agricultural Association (DeKalb AgResearch, Inc., Monsanto, Bayer). DeKalb County is credited with being the birthplace of the farm bureau movement.