At One Place

What airport is IAD?

IAD is
Washington Dulles International Airport
Washington, United States

Why the code is IAD

A deliberate scramble of DIA, which was too easily misread as DCA in handwriting.

This is the explanation in general circulation and it is very likely right, but no primary document has been published that settles it. Treated as an account rather than a fact.

The airport

IATA code
IAD
ICAO code
KIAD
Airport
Washington Dulles International Airport
City
Washington, United States
Opened
1962
Code origin
The usual account, unverified

Dulles opened with the code DIA, and controllers and clerks kept confusing handwritten DIA with DCA, the other Washington airport 30 miles away. The letters were reordered to IAD, which cannot be mistaken for anything. This is the account the airport authority itself gives, though no contemporaneous memo ordering the change has been published.

Codes it used to have

Code Until What happened
DIA 1968 Dulles International Airport. Reordered because handwritten DIA was being read as DCA.

Codes people book by mistake

Code What it actually is
DCA Reagan National, much closer to the city and the reason IAD is not DIA.

The other code, KIAD

Every airport has two codes. The three-letter IATA code, IAD, is the one on your boarding pass and your luggage tag, and it is assigned for commercial use. The four-letter ICAO code, KIAD, is the one pilots and controllers use, and it is assigned geographically: the first letter or two identify the region, so every airport in the same part of the world shares a prefix. That is why KIAD looks nothing like IAD.

Common questions

What airport is IAD?
Washington Dulles International Airport, in Washington, United States.
Why is Washington's airport called IAD?
A deliberate scramble of DIA, which was too easily misread as DCA in handwriting.
What is the difference between IAD and KIAD?
IAD is the IATA code, used commercially — tickets, timetables, luggage tags. KIAD is the ICAO code, used operationally by pilots and air traffic control, and assigned geographically by region.
Is IAD the same as DCA?
No. DCA is reagan National, much closer to the city and the reason IAD is not DIA.

Related pages

Sources

  1. Official vendor product documentation — At One Place

How these figures are compiled and checked