This article lists the airport at Saba as the worlds shortest runway at 1300 ft. The runway is built on a bit of flat land on the side of the volcano that makes up the island. Nowadays STOL aircraft land here, previously the aircraft had to come in skimming over the wave tops and zoom climb onto the runway.
The Twin Otter can land here. Does Saba really have the shortest runway on earth for FAR 23 commuter type aircraft, or are there any shorter ones?