Kotroni Airport (ICAO: LGKN) is a small airport situated northwest of Marathonas, Greece. It has one of the smallest runways in the world. Both runways are mostly used by helicopters because Kotroni is normally a base for the Hellenic Navy Helicopter Command. To indicate that helicopters land at the site, the airport has helipad signs on the surface of the runways. It also contains 4 helipads, which are on the runway and 16 helicopters' parking positions.

The terrain around Kotroni Airport is hilly to the north west, but to the southeast it is flat. A bay of the sea is near Kotroni Airport to the southeast. The highest point nearby is Mount Pentelicus, 1,109 meters above sea level, 8.7 km southwest of Kotroni Airport. Closest major community is Acharnes, 19.9 km west of Kotroni Airport. In the area around Kotroni Airport there are unusually many named peninsulas, islands and bays.