United States Fourth Fleet
2008 - Present
|Country||United States of America|
|Branch||United States Navy|
|Role||Direct Fleet Operations|
|Part of||U.S. Naval Forces Southern Command
U.S. Southern Command (USSOUTHCOM)
|Garrison/HQ||Naval Station Mayport|
|Rear Admiral Sinclair M. Harris|
U.S. Fourth Fleet is a United States Navy command operating the Navy component command of U.S. Southern Command (USSOUTHCOM). Fourth Fleet is headquartered on Naval Station Mayport in Jacksonville, Florida and is responsible for U.S. Navy ships, aircraft and submarines operating in the Caribbean, and Atlantic and Pacific Oceans around Central and South America.
U.S. Naval Forces Southern Command (USNAVSO) and U.S. FOURTH Fleet supports USSOUTHCOM joint and combined full spectrum military operations by providing principally sea based, forward presence to ensure freedom of maneuver in the maritime domain, to foster and sustain cooperative relationships with international partners and to fully exploit the sea as maneuver space in order to enhance regional security and promote peace, stability, and prosperity in the Caribbean, Central and South American regions.
U.S. Fourth Fleet was a major U.S. Navy command in the South Atlantic Ocean during World War II. It was originally established in 1943 to protect the U.S. against raiders, blockade runners and enemy submarines. In 1950, the Fourth Fleet was disestablished when its responsibilities were taken over by U.S. Second Fleet.
On April 24, 2008, then Chief of Naval Operations (CNO) Admiral Gary Roughead announced the reestablishment of the Fourth Fleet. Nearly three months later on July 12, 2008,it was re-established during a ceremony at Naval Station Mayport, Florida.
Fourth Fleet headquarters is co-located with USNAVSO headquarters in Mayport, Fla, and is commanded under a two-star admiral.
Commander, USNAVSO (COMUSNAVSO) retains missions as the Navy component commander for USSOUTHCOM. U.S. Fourth Fleet is responsible for U.S. Navy ships, aircraft and submarines operating in the USSOUTHCOM area of responsibility, which encompasses the Caribbean, Central and South America and surrounding waters. As part of the reestablishment, no new permanently stationed vessels will be assigned to U.S. Fourth Fleet, as it is an organizational fleet staffed to fulfill a planning and coordination mission.
U.S. Fourth Fleet will be focused on strengthening friendships and partnerships and will have five missions: support for peacekeeping, humanitarian assistance, disaster relief, traditional maritime exercises, and counterdrug support operations.
Previous Fourth Fleet Commanders
- Vice Admiral Jonas H. Ingram (September 1942 - November 11, 1944)
- Vice Admiral William R. Munroe (November 11, 1944 - April 15, 1945)
- Vice Admiral Thomas R. Cooley (1945 - mid 1946) 
- Vice Admiral Daniel E. Barbey (September 1946 - March 1947)
- Vice Admiral Charles McMorris (mid 1947 - July 1948)
- Rear Admiral Joseph D. Kernan (July 1, 2008 - June 12, 2009) 
- Rear Admiral Victor G. Guillory (June 12, 2009 - August 5, 2011)(Retired) 
- Rear Admiral Kurt W. Tidd (August 5, 2011 - June 22, 2012) 
- Rear Admiral Sinclair M. Harris (June 22, 2012 - Present) 
Reaction to reestablishment
This reactivation, without informing regional governments, sparked concern within some South American governments. The governments of Argentina and Brazil made formal inquiries as to the fleet's mission in the region. In Venezuela, President Hugo Chavez accused the United States of attempting to frighten the people of South America by reactivating the fleet  and vowed that his country's new Sukhoi Su-30 jets could sink any U.S. ships invading Venezuelan waters. Cuban ex-president Fidel Castro warned that it could lead to more incidents such as the 2008 Andean diplomatic crisis. 
Fourth Fleet Ships
No ships are permanently assigned to the Fourth Fleet. Ships homeported in the United States Fleet Forces Command and United States Third Fleet routinely deploy to the Fourth Fleet area of responsibility (AOR), during which time they are under the operational control of the Fourth Fleet Commander. This is consistent with ships deploying to the other numbered fleets (Fifth, Sixth, and Seventh Fleets), although all of those fleets have at least one permanently assigned ship.
- United States Fleet Forces Command
- United States Second Fleet
- United States Third Fleet
- United States Fifth Fleet
- United States Sixth Fleet
- United States Seventh Fleet
- United States Tenth Fleet
- "Navy Reestablishes U.S. Fourth Fleet". United States Navy. April 24, 2008.
- "HyperWar The Official Chronology of the U.S. Navy in World War II". United States Navy. June 1, 2006.
- "HyperWar The Official Chronology of the U.S. Navy in World War II". United States Navy. June 5, 2012.
- "Biography of Thomas Ross Cooley". United States Navy. June 1, 2006.
- "Papers of Vice Admiral Daniel E. Barbey, 1941-1969". Naval Historical Center. June 1, 2006.
- "Biography of Joseph D. Kernan". United States Navy. June 5, 2012.
- "Biography of Victor G. Guillory". United States Navy. June 5, 2012.
- "Biography of Kurt W. Tidd". United States Navy. June 5, 2012.
- "Biography of Sinclair M. Harris". United States Navy. June 22, 2012.
- "Chavez attacks the Fourth Fleet at the start of parade / Chávez arremete contra la IV Flota en el inicio del desfile militar". www.noticias24.com. July 5, 2008.
- "Fourth Fleet to intervene to Latin America tomorrow / IV Flota de intervención hacia Latinoamérica mañana". www.rlp.com.ni. June 30, 2008.
Karen Domabyl Smith et al. (January 2002). "Is NAVSO Organized and Staff To Do Its Job" (PDF) (in English). Alexandria, Virginia: Center for Naval Analyses. Retrieved 2011-09-03. "CRM D0005057.A1/Final"
- COMUSNAVSO/C4F Official Website
- Numbered Fleets by the Federation of American Scientists
- Navy Times: 4th Fleet returns, gunning for drug smugglers
- Northshorejournal.org, Fourth Fleet is about partnerships