Adriatic Sea southeast, the Adriatic Sea connects to the Ionian Sea at the wide Strait of Otranto. The International Hydrographic Organization (IHO) defines the boundary between the Adriatic and the Ionian seas as a line running from the Butrinto River's mouth (latitude 39°44'N) in Albania to the Karagol Cape in Corfu, through this island to the Kephali Cape (these two capes are in latitude 39°45'N), and on to the Santa Maria di Leuca Cape (latitude 39°48'N). It extends from the northwest to the southeast and is wide. It covers and has a volume of . The Adriatic extends northwest from 40° to
Ionian Sea Sea, and from Piraeus westward. Calypso Deep, the deepest point in the Mediterranean at , is located in the Ionian Sea, at . The sea is one of the most seismically active areas in the world. The name "Ionian" comes from the Greek language . Its etymology is unknown. Ancient Greek writers, especially Aeschylus, linked it to the myth of Io. In Ancient Greek the adjective "Ionios" () was used as an epithet for the sea because Io swam across it. According to the "Oxford Classical Dictionary", the name may derive from Ionians who sailed to the West. There were