Many, many more than I would have thought. This is a partial list; I haven't even exhausted the 'ka' group yet; there are several others.
The largest country in the world is Russia and has more than four letters, but the largest continent in the world is Asia with four letters.
Mint
Ares
Brno
You tell me :P
JunkJambJustJoinJail
Nice.
Moth comes to mind .
Lyon (in France).
Doha (capital of Qatar)
Taos
BRNO (City in Czech Republic)