The 2nd Fleet of the United States Navy is responsible in peacetime for training the Atlantic battle fleet in war-fighting skills, developing and evaluating new naval tactics and maintaining theater battle group readiness. It was activated in the aftermath of the World War II, when it was recognised that a numbered fleet was needed for the Atlantic.

Second Fleet operates primarily in the Atlantic Ocean from the North Pole to the South Pole and from the shores of the United States to the west coast of Europe. It also operates along both coasts of South America and part of the west coast of Central America. In all, it covers more than 38 million square miles (98 million km²). The US Second Fleet is a part of US Joint Forces Command. Based in Norfolk, Virginia, Second Fleet has USS Mount Whitney as the fleet flagship. The force consists of a balanced mix of capabilities including aircraft carriers, surface combatants, submarines, surveillance assets, amphibious forces, marine landing and mobile logistic units.