DeKalb County Government City, County & State Government DeKalb County Government Visit Website 200 North Main Street Sycamore, IL 60178 (815) 895-1630 (815) 895-7284 (fax) Facebook About About Welcome to DeKalb County, Illinois, located just 60 miles west of Lake Michigan. Visit us in person to experience the blend of country charm and proximity to education, business and entertainment that create a unique quality of life.