ICAO airport code prefixes
Unlike IATA codes, four-letter ICAO codes are geographic: the first letter tells you the world region. Read KJFK as K (the contiguous United States) plus JFK. Here is the broad first-letter scheme with examples.
How ICAO codes are structured
An ICAO location indicator has four letters. The first letter, and often the second, encodes the region and country; the remaining letters identify the specific airport. So EGLL is E (northern Europe), G (the United Kingdom) and LL for London Heathrow. The matching IATA code, LHR, carries no such geography. See IATA vs ICAO for the full comparison.
ICAO first-letter regions
The counts and the examples below are not illustrations picked by hand. They are the airports in this site’s own dataset whose ICAO code starts with that letter, counted at the last regeneration, with the three busiest of them by route connections. Every example links to its page, so you can check the claim in one click.
| First letter | Region | Airports | Busiest three |
|---|---|---|---|
| K | Contiguous United States | 1,578 | KATL, KORD, KLAX |
| P | Alaska, Hawaii and the eastern Pacific | 243 | PHNL, PANC, PHOG |
| C | Canada | 426 | CYYZ, CYUL, CYVR |
| T | The Caribbean | 50 | TJSJ, TNCM, TNCA |
| M | Mexico and Central America | 318 | MMMX, MMUN, MPTO |
| S | South America | 850 | SBGR, SKBO, SPJC |
| B | Greenland, Iceland and Kosovo | 45 | BIKF, BKPR, BGGH |
| E | Northern Europe | 397 | EGLL, EDDF, EHAM |
| L | Southern Europe and the Mediterranean | 456 | LFPG, LEBL, LTFM |
| U | Russia and most post-Soviet states | 329 | UUDD, UUEE, ULLI |
| O | The Middle East and Pakistan | 271 | OMDB, OMAA, OEJN |
| V | South and Southeast Asia | 395 | VHHH, VTBS, VIDP |
| W | Maritime Southeast Asia | 307 | WSSS, WMKK, WIII |
| R | East Asia (Japan, Korea, Taiwan) | 209 | RKSI, RJAA, RCTP |
| Z | China, Mongolia and North Korea | 320 | ZBAA, ZSPD, ZGGG |
| Y | Australia | 576 | YSSY, YBBN, YMML |
| N | The South Pacific | 218 | NZAA, NFFN, NTAA |
| F | Southern and central Africa | 501 | FAOR, FKKD, FNLU |
| G | Western Africa and the north-west | 114 | GCTS, GCLP, GMMN |
| H | North-eastern Africa | 237 | HECA, HKJK, HAAB |
| D | Parts of West Africa | 144 | DAAG, DTTA, DNMM |
This is the broad scheme; a few regions split further on the second letter, and a handful of territories are grouped for historical reasons. That is why a letter’s count can include airports outside the region named here.
Frequently asked questions
What does K mean in an ICAO code?
K is the ICAO prefix for the contiguous United States. So JFK becomes KJFK, LAX becomes KLAX, and O'Hare becomes KORD.
Why does JFK become KJFK?
JFK is the three-letter IATA code. The four-letter ICAO code adds the regional prefix K (contiguous US) to the front, giving KJFK. The two codes describe the same airport for different users.
Are IATA codes geographic like ICAO codes?
No. IATA three-letter codes are not systematically geographic, so you cannot tell the country from an IATA code. ICAO four-letter codes are, because the first letter (or two) encodes the region.
Keep reading: IATA vs ICAO · How airport codes work · all guides.