IDOT's roots can be traced back over a century. For as long as there have been cars, highways, and air traffic, there has been an Illinois transportation agency. The rich history of our department spreads across the entire state. From massive bridges spanning the Mississippi or Illinois Rivers to winding roads eloquently carved into limestone bluffs. And, from two-lane roads tracing through rural corn and soybean fields to dirt and grass landing strips to the steel and concrete jungle of O’Hare International Airport, and on every mile of interstate and railroad that made Illinois what it is today, the mark of an Illinois transportation agency can be seen and felt.