The Fleet concept came into being following the Spanish-American War when new bases acquired in the Caribbean and the Pacific were considered useless unless protected by an adequate fleet. The United States Atlantic Fleet was established under one command in 1906 by President Theodore Roosevelt. The Asiatic and Pacific squadrons remained separate commands until April 15, 1907, when they were combined to form the United States Pacific Fleet. President Roosevelt placed great emphasis on naval readiness for war. During his first administration, from 1901 to 1905, authorization was obtained from Congress for 10 new battleships, four armored cruisers and 17 smaller craft. All battleships were assigned to the Atlantic Fleet and all armored cruisers and lighter cruisers were assigned to the newly created Pacific Fleet.
In 1922, the Pacific and Atlantic Fleets were combined to form the United States Battle Fleet, which positioned a main body of ships in the Pacific, and the Scouting Fleet in the Atlantic. Other units were attached to the Asiatic Fleet. In the mid-1920's, the internal struggle for power in China was accompanied by many acts of violence against foreigners. Units of the Yangtze Patrol, reinforced by destroyers and light cruisers from the US Asiatic Fleet, steamed upriver to protect Americans and national interests.
On 01 February 1941, General Order 143 reorganized the United States Fleet into three separate fleets (Atlantic, Pacific and Asiatic). The Order further stated each fleet would be under the command of a full admiral. This administrative reorganization of the Fleet, by dividing the forces between two oceans, was the beginning of the independent development of forces according to strategic requirements of each region.
Current Atlantic and Pacific Fleet missions reflect changes since the US Congress passed the Goldwater-Nichols Act of 1986 to engender more cooperation and "jointness" between the armed services. The Fleets' role transitioned from that of warfighter to that of force provider, sustainer and trainer for the unified commanders.
Atlantic Fleet responsibilities include the training, maintenance, and readiness of naval forces deployed to the Mediterranean and Caribbean seas, South America, and the Persian Gulf. Atlantic Fleet is also responsible for the operations of most U.S. Navy bases and facilities along the East and Gulf coasts of the United States, in Puerto Rico, Cuba, and Iceland. The Atlantic Fleet executes an annual budget of $5 billion to maintain, train, and operate a force of 125,000 active duty sailors, nearly 200 ships, and more than 1,300 Navy aircraft. On 01 February 1991, the Commander in Chief, US Atlantic Fleet became the naval component commander for the Commander in Chief, US Southern Command, assuming responsibility for all US Navy operational and training matters in the USSOUTHCOM area of responsibility. And on 01 June 1992, the Commander in chief, US Atlantic Fleet became the naval component commander for the Commander in Chief, US Strategic Command, assuming responsibility for all US Navy operational and training matters under USSTRATCOM.
Pacific Fleet is the world's largest naval command, extending from the west coast of the United States to the east coast of Africa, from the North Pole to the South Pole, encompassing two oceans, six continents, and more than half the surface of the earth. Each day, Pacific Fleet ships are at sea in the Pacific, Indian, and Arctic Oceans, from the west coast of the U.S. to the Arabian Gulf. The Pacific Fleet encompasses approximately 200 ships, 2,000 aircraft and 250,000 Sailors and Marines. Pacific Fleet supports the US Pacific Command's theater strategy, and provides naval forces to USCINCPAC and other US unified commanders. Pacific Fleet's heritage dates to 1821 with the establishment of the Pacific Squadron, which initially confined its activities to the waters off South America. In March 1854 Commodore Matthew C. Perry negotiated and signed a treaty opening Japan to trade with other nations for the first time in 300 years. The Spanish-American War of 1898 resulted in further expansion of American naval power in the Pacific. In the post-Vietnam period Pacific Fleet responsibilities expanded to include the Indian Ocean, where aircraft carrier battle groups operate in support of US national interests in the volatile part of the world.