The district is a historic U.S. transportation and shipping hub; not only does it include Chicago Midway International Airport, but it is also traversed by the Chicago Sanitary and Ship Canal, the Calumet Sag Channel, and the Des Plaines River, earning national designations for the Chicago Portage National Historic Site in Forest View and the Illinois and Michigan Canal National Heritage Corridor. The path of historic Route 66 runs southwest through the district from its eastern end in Chicago. Interstate 55 intersects with both the Tri-State Tollway (Interstate 294) and the Dan Ryan Expressway (Interstate 90/94) in the district, and in 2001 – since which time the district has shifted slightly to the northwest – it was noted as likely having more freight yards and railroad crossings than any other district.