Originally Posted by shoeless1920

If I'm not mistaken, many years ago the three-letter IATA code for Chicago Municipal Airport on the SW side of the city used to be CHI. In 1949, Chicago Municipal was renamed Chicago Midway to honor the Battle of Midway and its IATA code was changed to MDW. Fair enough.
Meanwhile, in 1945, the Douglas Aircraft factory on the NW side of Chicago was closed down after WWII ended, and its associated airfield was given its historical name, Orchard Field, and the IATA code was ORD. In 1949, Orchard Field was renamed O'Hare Field to honor the famed WWII fighter pilot, Butch O'Hare. I've been unable to confirm if there's a specific reason why the IATA code was left at ORD despite renaming the airport. I realize that ORD didn't become Chicago's big main commercial airport for another ten years, so maybe ORD was determined to be "close enough" and it "didn't need" to be changed; however, does anyone know the real reason? Thank you!!
P.S.: I just noticed that Pal-Waukee Airport (PWK) at the northwest corner of Palatine Road and Milwaukee Avenue in north suburban Wheeling, IL, was re-named Chicago Executive Airport at some point, while the IATA code remains PWK. Maybe they simply just don't always change IATA codes when airport names undergo a change?