---
title: "IAD is which airport? Washington"
description: "IAD is Washington Dulles International Airport in Washington, United States. Where the code comes from, and the codes it gets mixed up with."
url: https://atoneplace.net/airport/iad/
site: "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

- [United States](https://atoneplace.net/country/united-states/)
- [The flag of United States](https://atoneplace.net/flag/united-states/)
- [Airport codes in United States](https://atoneplace.net/airport/in/united-states/)
- [What airport is DCA?](https://atoneplace.net/airport/dca/)
- [What airport is JFK?](https://atoneplace.net/airport/jfk/)
- [What airport is LAX?](https://atoneplace.net/airport/lax/)
- [What airport is ORD?](https://atoneplace.net/airport/ord/)
- [What airport is ATL?](https://atoneplace.net/airport/atl/)
- [What airport is MCO?](https://atoneplace.net/airport/mco/)
- [What airport is DFW?](https://atoneplace.net/airport/dfw/)
- [What airport is EWR?](https://atoneplace.net/airport/ewr/)
- [What airport is SFO?](https://atoneplace.net/airport/sfo/)

## Sources

- Official vendor product documentation — At One Place (/about/)