The Garabogazkoel (also spelt Kara-Bogaz-Gol; "Black Strait Lake"), or Garabogazkoel Aylagy ("Black Strait Lake Bay"), is a shallow, water-filled, highly-saline depression in the northwestern corner of Turkmenistan. 

It forms a lagoon of the Caspian Sea and has a variable surface area, about 18,000 km2 (6,900 sq mi).