Commander Undersea Surveillance

Commander Undersea Surveillance (CUS), originally established as Commander, Oceanographic System Atlantic (COSL) in 1954, was a key U.S. Navy command responsible for managing the Sound Surveillance System (SOSUS). Its mission focused on the operation, maintenance, and coordination of undersea listening arrays used to detect and track foreign submarines, particularly during the Cold War. Renamed Commander Undersea Surveillance in 1985, the unit’s oversight expanded to include all U.S. Navy fixed undersea surveillance systems worldwide. CUS played a crucial role in anti-submarine warfare until its functions were merged into other naval commands during the post-Cold War restructuring of the 1990s.