You're standing in an airport in London, or maybe Tokyo, looking at a luggage tag. It says ORD. If you didn't know better, you’d think the airline was sending your bags to Orchard Park or maybe some random field in Oregon. But no, that is the official code for O'Hare Airport in Chicago. It’s one of those weird travel quirks that everyone just accepts, yet almost nobody can actually explain when put on the spot.
It makes zero sense at first glance. LAX is Los Angeles. MIA is Miami. PHX is Phoenix. So why isn't Chicago O'Hare something like CHO or OHA?
The answer is buried under layers of aviation history, a defunct orchard, and a war hero whose name didn't even grace the airport until years after the code was already etched into the books. If you’ve ever wondered why your boarding pass looks like a typo, you aren't alone. It’s a legacy of how the aviation industry grew up—fast, messy, and a little bit disorganized.
The "Orchard" in the Code for O'Hare Airport
Back in the 1940s, the world was a different place. Chicago was already a rail hub, but it needed to be a flight hub too. During World War II, the Douglas Aircraft Company needed a spot to build C-54 military transport planes. They chose a site about 15 miles northwest of downtown Chicago. At the time, that area was basically just a small community called Orchard Place.
The military called the plant "Orchard Place Airport."
When the International Air Transport Association (IATA) started standardizing these three-letter identifiers, they pulled from the existing name. They took the "OR" from Orchard and the "D" from Douglas. ORD. Simple as that. It was a functional, boring military designation that was never really meant to be a brand name for the second-busiest airport in the world.
By the time the city of Chicago decided to rename the facility in 1949 to honor Lieutenant Commander Edward "Butch" O'Hare—a Medal of Honor recipient and naval aviator—the ORD code was already "sticky."
Changing an airport code isn't like changing a Twitter handle. It involves updating global flight manifests, pilot charts, baggage routing systems, and government databases across the entire planet. Once a code is in the system and working, the aviation world generally decides to just live with it. That’s why we still use ORD today, nearly 80 years after the orchard disappeared.
Why We Don't Use CHI or OHA
You might think, "Well, why didn't they just use CHI?"
They actually do, sort of. In the world of global distribution systems (GDS) used by travel agents and booking sites, CHI is a "metropolitan area code." It represents all of Chicago's major airports, including Midway (MDW) and Rockford (RFD). If you search for a flight to CHI, the system looks for any of those. But a specific plane can’t land at a "metropolitan area." It has to land on a specific strip of asphalt.
Each physical location needs a unique three-letter identifier.
As for OHA? By the time O'Hare was becoming a household name, other codes were already snatched up. Every combination of three letters is a finite resource. There are only $26^3$ possible combinations, which is 17,576. That sounds like a lot, but when you factor in every tiny municipal airstrip, military base, and private landing pad on Earth, the "good" names go fast.
The N-Code Problem
There is another weird rule in the U.S. that most people don't know about. The Federal Aviation Administration (FAA) generally reserves identifiers starting with the letter "N" for the Navy. This is why Newark is EWR instead of NEW or NRK. If Chicago had tried to use a code starting with N, they would have been blocked.
Similarly, the letter "W" is often reserved for the Federal Communications Commission (FCC) to use for radio and TV station call signs east of the Mississippi.
The aviation industry is a giant puzzle of legacy rules. The code for O'Hare Airport is a perfect example of a "legacy bug" that became a feature. It’s a badge of honor for Chicagoans now. If you have an ORD sticker on your laptop, it’s a subtle signal that you know your way through the neon-lit underground tunnel in Terminal 1.
Navigating the ORD Identity Crisis
Honestly, O'Hare is a bit of a beast. It’s massive. It’s loud. It’s frequently delayed by lake-effect snow. But it is also a masterclass in logistics.
The airport covers over 7,000 acres. That’s roughly 5,300 football fields. Because it’s a "hub and spoke" center for United and American Airlines, the ORD code is one of the most frequently printed sequences of letters in the history of human travel.
Think about the sheer volume. On a busy day, O'Hare handles about 2,500 flights. That’s roughly one takeoff or landing every 30 seconds. Every single one of those pilots, air traffic controllers, and ground crew members is looking at those three letters: ORD.
The Butch O'Hare Connection
It’s worth noting who the airport is actually named after, because the story is incredible. Butch O'Hare was a pilot who, in 1942, single-handedly defended his aircraft carrier from a swarm of Japanese bombers. He had limited ammunition and no wingman. He took down five planes and damaged a sixth. He was the Navy's first ace of World War II.
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When he went missing in action in 1943, the city of Chicago wanted to do something massive to honor him.
The renaming of Orchard Field to O'Hare International Airport was a huge deal. It was a way to move past the war and look toward a future where Chicago was the center of the world's "inland" trade. But even with all that prestige, the ORD code stayed. It’s a weird juxtaposition: a name honoring a high-flying war hero and a code honoring a long-dead fruit patch.
Surprising Facts About O'Hare's Infrastructure
Most people see the code for O'Hare Airport and think of Terminals 1, 2, 3, and 5. Wait, where is Terminal 4?
This is my favorite piece of O'Hare trivia. Terminal 4 existed, but it was a temporary solution. In the late 80s and early 90s, while the new International Terminal (Terminal 5) was being built, the airport used the ground floor of the parking garage as a temporary international arrivals area. They called it Terminal 4. Once Terminal 5 opened in 1993, Terminal 4 was retired to avoid confusing the shuttle bus drivers.
They never renumbered the others.
So now, you just skip from 3 to 5. It’s a very Chicago way of doing things. "If it ain't broke, don't fix it, but also we're not going to change the signs."
The Multi-Modal Hub
ORD isn't just about planes. It’s one of the few airports in the U.S. where you can take a heavy rail train (the CTA Blue Line) directly into the heart of the terminal. You don't have to take a shuttle to a station; you just walk out of baggage claim and follow the signs.
This connectivity is part of why the ORD code is so valuable. It represents a massive intersection of global commerce. Whether you’re shipping deep-dish pizzas via cargo or flying in for a business meeting at the Merchandise Mart, ORD is the gate.
Actionable Tips for Using the Code for O'Hare Airport
If you're flying into or out of ORD, you need to be smart about it. This isn't a "show up 45 minutes early" kind of place.
- Check the Terminal for the Airline, Not Just the Code: Because O'Hare is a hub for two giants, United and American, they dominate different terminals. United is mostly Terminal 1. American is mostly Terminal 3. Terminal 5 is almost all international, but some domestic carriers like Delta and Southwest have moved there recently. Don't just tell your Uber driver "O'Hare." Tell them the terminal.
- The ORD-MDW Transfer: If you are booking a "connecting" flight through Chicago, double-check that both flights are at ORD. Some discount travel sites will sell you a ticket that arrives at Midway (MDW) and departs from O'Hare (ORD). That is a 30-mile trek through some of the worst traffic in America. You will miss your flight.
- Global Entry and Mobile Passport: ORD was one of the first airports to go heavy on biometric screening. If you are coming back from abroad, use the Mobile Passport Control app if you don't have Global Entry. The lines at Terminal 5 can be legendary (in a bad way).
- The Hidden Oasis: If you have a long layover at ORD, head to the Rotunda in Terminal 3. It’s one of the few places with a bit of "old school" airport glamour, and it’s usually quieter than the main concourses. There's also an urban garden in Terminal 3 where they grow greens for the airport restaurants. It's a nice break from the "ORD" madness.
The code for O'Hare Airport is more than just a relic of an old orchard. it’s a symbol of how Chicago operates—built on history, slightly confusing to outsiders, but incredibly efficient once you know the secret. Next time you see those three letters on your suitcase, just remember you're carrying a tiny piece of a 1940s Douglas aircraft plant with you.
When navigating O'Hare, always prioritize the Blue Line for downtown access to avoid the Kennedy Expressway congestion, and download the Ventra app beforehand to skip the fare machine lines. If you're stuck in Terminal 1, the neon tunnel between Concourses B and C is the best place to stretch your legs—it's 744 feet of light and sound that makes the ORD experience feel a little more like the future and a little less like a history lesson.