Understanding the aviation codes assigned to the Chicago metropolitan area—ORD, MDW, and RFD—helps you plan your itineraries efficiently across the region's complex airspace network. Each designator serves a specific operational purpose, routing millions of commercial passengers and cargo shipments through Illinois every year.
O'Hare International Airport (ORD), Midway International Airport (MDW), and Chicago Rockford International Airport (RFD) form a tripartite system that separates heavy international transit, domestic point-to-point low-cost carrier operations, and regional cargo freight. Knowing which code belongs to which airfield prevents costly booking mistakes, missed connections, and wrong-terminal arrivals.
O'Hare International Airport (ORD)
Located approximately 18 miles northwest of downtown Chicago, O'Hare International Airport carries the IATA code ORD and the ICAO code KORD. The designation originates from its history as a World War II manufacturing plant and airfield named Orchard Place, which later became Orchard Field before renaming in honor of World War II flying ace Lieutenant Commander Edward "Butch" O'Hare.
Today, O'Hare functions as a primary global super-hub. It features an extensive layout with multiple active runways and four active passenger terminals (Terminals 1, 2, 3, and 5).
- Hub Status: It serves as a primary domestic and international hub for United Airlines and a major operational base for American Airlines.
- Global Reach: Passengers can fly nonstop to over 240 destinations worldwide, spanning North America, Europe, Asia, South America, and the Middle East.
- Cargo Operations: Beyond passenger transit, O'Hare handles massive volumes of international air freight, anchoring regional logistics supply chains.
- Transit Connectivity: Travelers moving between ORD and the city center can take the Chicago Transit Authority (CTA) Blue Line train, running 24 hours a day directly from Terminal 2.
Midway International Airport (MDW)
Situated just 8 miles southwest of the Loop, Midway International Airport is designated by the code MDW (ICAO: KMDW). Originally established in 1923 as Chicago City Airport and later named Chicago Municipal Airport, it gained the name Midway in 1949 to honor the Battle of Midway.
Midway offers a compact, single-terminal setup with 43 gates housed under a central concourse. This streamlined layout makes walking distances significantly shorter than at O'Hare.
- Low-Cost Carrier Dominance: Southwest Airlines operates its largest focus city and primary crew base here, joined by carriers like Volaris and Delta Air Lines.
- Point-to-Point Network: Instead of operating massive international banks, Midway focuses on high-frequency domestic and near-international (Mexico, Caribbean) routes.
- Urban Proximity: Because it sits closer to downtown Chicago than O'Hare, taxi and rideshare times to the Loop are often shorter, supplemented by the CTA Orange Line rapid transit station located adjacent to the terminal.
Chicago Rockford International Airport (RFD)
While O'Hare and Midway handle the immediate urban core, Chicago Rockford International Airport—operating under the code RFD (ICAO: KRFD)—sits roughly 80 miles northwest of Chicago in Rockford, Illinois.
RFD functions primarily as an alternative commercial passenger gateway and a massive cargo powerhouse.
- Passenger Experience: Low-cost carriers such as Allegiant Air utilize RFD to offer budget-friendly leisure flights to destinations in Florida and Arizona, allowing travelers to bypass big-city traffic, long security lines, and expensive parking fees.
- Cargo Giant: RFD ranks among the top cargo airports in the United States by landed weight, serving as a primary Midwest hub for UPS and other global logistics operators.
- General Aviation: The facility supports extensive flight training, corporate aviation, and maintenance services, relieving congestion from the busier Chicago airspace.
Operational Differences and Practical Travel Tips
Choosing the correct airport code saves time and eliminates ground transit stress. Here are factors to weigh when booking travel through Chicago:
- Connecting Flights: If your itinerary requires a tight connection, verify whether you need to transfer between ORD and MDW. A ground transfer across Chicago can take anywhere from 45 minutes to over two hours depending on traffic on the Kennedy (I-90) or Stevenson (I-55) expressways.
- Airline Alliances: Major network carriers heavily concentrate operations at O'Hare, while low-cost carriers dominate Midway and smaller leisure routes appear out of Rockford.
- Ground Alternatives: If parking rates or traffic congestion at O'Hare deter you, check flight availability out of RFD or Midway as practical alternatives for regional trips.
Frequently Asked Questions
What does the airport code ORD stand for?
The code ORD derives from the airfield's original historical name, Orchard Field, which dated back to its origins as a World War II aircraft manufacturing site before its renaming in 1949.
Can I easily travel between O'Hare and Midway using public transit?
Yes. You can take the CTA Blue Line train from O'Hare into downtown Chicago, transfer to the Loop subway or walk to a downtown station, and catch the CTA Orange Line out to Midway. The total transit time takes approximately 90 minutes.
Why do some flights list KORD instead of ORD?
Aviation authorities use two different standards. IATA issues three-letter codes (like ORD) primarily used on passenger boarding passes, luggage tags, and booking systems. ICAO adds a regional prefix to create four-letter codes (like KORD) used by pilots and air traffic control for flight planning and radio communications.
Is Rockford Airport (RFD) considered part of Chicago?
Geographically, RFD is located in Rockford, Illinois, about 80 miles away from downtown Chicago. However, airlines market it as a convenient regional alternative for travelers living in northern Illinois and southern Wisconsin who want to avoid O'Hare's congestion.
