History
History of U.S. Naval Forces Southern Command

South Atlantic Force (SOLANT) was renamed United States Naval Forces Southern Command (USNAVSO) on February 17, 2000 and headquartered at Naval Station Roosevelt Roads, Puerto Rico.  It later relocated to Naval Station Mayport, Florida in early 2004. On February 28, 2023, the command short title officially changed to USNAVSOUTH. USNAVSOUTH serves as a main link between the U.S. Navy and the navies of South America, Central America, and the Caribbean, and is at the forefront of U.S. engagement in the Western Hemisphere. The command consolidates functions previously conducted by the former Western Hemisphere Group, Mayport, Florida and former SOLANT, Naval Station Roosevelt Roads, Puerto Rico. USNAVSOUTH was built around the core of SOLANT, which was originally established on September 3, 1942, and eventually headquartered at Roosevelt Roads, Puerto Rico in 1973. SOLANT had participated in annual “UNITAS” deployments around South America since 1960 and routinely deployed to Africa for the West African Training Cruise since 1980.

In addition to UNITAS, USNAVSOUTH participates in Navy and joint exercises, counter-illicit trafficking operations, port visits, humanitarian missions, disaster relief and protocol events. USNAVSOUTH exercises military command and control of all assigned/allocated ships and units, and serves as the Navy component command to U.S. Southern Command (USSOUTHCOM) with respect to naval matters in the region.

History of U.S. 4th Fleet

U.S. FOURTH Fleet employs maritime forces in cooperative maritime security operations in order to maintain access, enhance interoperability, and build enduring partnerships that foster regional security in the USSOUTHCOM AOR. On April 24, 2008, Chief of Naval Operations (CNO) Admiral Gary Roughead announced the re-establishment of U.S. Fourth Fleet. He officially re-established U.S. FOURTH Fleet effective May 5, 2008 with a formal ceremony held at Naval Station Mayport on July 12, 2008. The original FOURTH Fleet was a major U.S. Navy command in the South Atlantic Ocean during World War II. It was first established on March 15, 1943 to protect the U.S. against raiders, blockade runners and enemy submarines until renamed Task Force 27 on April 15, 1945 then dissolved in the fall of the same year. 

On January 10, 1946, the FOURTH (Reserve) Fleet was reactivated to initiate the Reserve Training Program in support of Emergency Plan White until January 1, 1947 when, in accordance with NavOp #14, it was dissolved. On January 1, 1947, Vice Adm. D. E. Barbey hauled down his flag as Commander FOURTH Fleet. Commander, Service Force Atlantic Fleet (COMSERVLANT) assumed the duties of Commander, FOURTH Fleet for the preparation and implementation of Emergency Plan White. 

Today U.S. FOURTH Fleet headquarters is co-located with U.S. Naval Forces Southern Command (USNAVSOUTH) at Mayport, Fla.  The U.S. FOURTH Fleet Commander is also Commander, U.S. Naval Forces Southern Command (COMUSNAVSOUTH). FOURTH Fleet is responsible for U.S. Navy ships, aircraft and submarines operating in the USSOUTHCOM area of operations (AOR), which encompasses the Caribbean, Central and South America and surrounding waters.