Commodore was an early title and later a rank in the United States Navy, United States Coast Guard and also has been a rank in the United States Public Health Service Commissioned Corps and the National Oceanic and Atmospheric Administration Commissioned Officer Corps (NOAA Corps) and its ancestor organizations. For over two centuries, the designation has been given varying levels of authority and formality.
Today, it is no longer a specific rank within active-duty or reserve forces or in the Public Health Service Commissioned Corps or NOAA Corps, but it remains in use as an honorary title within the U.S. Navy and U.S. Coast Guard for those senior captains (pay grade O-6) in command of operational organizations composed of multiple independent subordinate naval units, e.g., multiple independent ships, submarines, or aviation squadrons.