Breton Sound () is a sound of the Gulf of Mexico and a part of the coastline of the U.S. state of Louisiana. It lies off the southeast coast of the state and is partially enclosed by the Breton Islands. Two ships in the United States Navy have been named the USS Breton after this area. On August 29, 2005, Hurricane Katrina crossed the sound before making its third landfall near Pearlington, Mississippi. External links Environmental Atlas of Lake Pontchartrain Phytoplankton of the Breton Sound estuary Bodies of water of Louisiana Bodies of water of Plaquemines Parish, Louisiana Bodies of water of St. Bernard Parish, Louisiana Sounds of the United States Estuaries of Louisiana