Despite playing an active and decisive role in the
American Civil War, in the following years the
U.S. Navy fell into precipitous decline. A lack of both federal funding and public interest reduced the Navy's size, prestige, and technological superiority; whereas steel ships were increasingly the norm, the U.S. Navy was entirely wooden. Towards the end of the 19th century, American naval power had become vastly obsolete compared to Europe, and even lagged behind the navies of less developed nations such as
Chile. In an era of
rapid industrialization,
globalized commerce, and
colonial expansion,
Alfred Thayer Mahan's ideas about the importance of
sea power, expressed in his book
The Influence of Sea Power upon History were adopted wholesale by the U.S. Navy. Navalists saw sea power as crucial for U.S. commercial and strategic interests, as well as a source of national prestige and power projection. American naval officers and military strategists advocated for a larger and more technologically advanced navy that could protect the U.S.'s vast maritime borders, safeguard its commercial interests, and project power abroad. Among the leading reformers was Navy Lieutenant
Theodorus Bailey Myers Mason, who called for the creation of a naval intelligence office dedicated to gathering information on foreign navies and the latest in naval science to help rebuild the U.S. Navy.
William H. Hunt, who served briefly as
Secretary of the Navy under President
James Garfield, formed a
Naval Advisory Board tasked with rebuilding the Navy and bringing it up to par to global standards. Largely in response to Mason's recommendations, on March 23, 1882, Hunt issued General Order No. 292, which read: The new Office of Naval Intelligence would be headquartered in the State, War and Navy Building (now the
Old Executive Office Building), with Mason appointed as its first "Chief Intelligence Office". As originally conceived, ONI assisted in the Navy's advancement by dispatching
naval attachés around the world to acquire data and resources related to the latest in naval warfare. These findings would be analyzed, interpreted, and disseminated to Navy leaders and government officials, helping to inform policies and programs related to naval development. American entry into the
First World War in 1917 marked a turning point in the office's history. President
Woodrow Wilson was an exponent of the importance of a strong navy to U.S. defense. Under his administration, Congress authorized ONI's first major increase in personnel and funding, and expanded its role to include domestic security operations — namely the protection of U.S. ports, harbors, and maritime facilities from enemy infiltration and sabotage. ONI's mandate often entailed partnering with the departments of State, War, Justice, Commerce, and Labor. Due to the increasingly sensitive nature of its work, ONI also began to censor radio and mail communications, which further marked its development as a major intelligence office. During the 1920s and 1930s, many of ONI's activities were dedicated to
Japan, which was an increasingly advanced and
belligerent naval power. The office investigated Japanese fortifications in the Pacific, acquired information on Japanese military aircraft and weaponry, and partnered with the U.S. Army's
Military Intelligence Division and the
Federal Bureau of Investigation to monitor potentially subversive elements within the
Japanese American community; ONI's director, Rear Admiral
Walter Stratton Anderson, met weekly with his counterparts in the FBI and MID to gather and share information on suspected internal threats. In 1929,
Chief of Naval Operations William D. Leahy made permanent ONI's functions as an intelligence office, while in 1939, President
Franklin D. Roosevelt granted the office considerable authority on matters of domestic security. In the run up to Pearl Harbor, ONI was beset with challenges including disagreements with the
Chief of Naval Operations and the
FBI on who would in charge of naval counterintelligence both outside and with the borders of the United States. Partly as result of these challenges, ONI had four directors in the year 1941.
World War II Following Japan's
attack on Pearl Harbor in 1941, concerns about subversive activity by Japanese Americans grew more pressing. ONI commissioned Kenneth Ringle, assistant district intelligence officer for the
Eleventh Naval District in Los Angeles, to conduct a thorough investigation of the resident Japanese population. He found little evidence of Japanese American saboteurs, and in his final report to President
Roosevelt, advised against
mass incarceration, a view that was shared by most ONI officials, but that was largely ignored by the Army and
War Department. The
Second World War would see another expansion of ONI's duties and a subsequent increase in its budget and staff. The office established two intelligence schools that trained hundreds of Intel officers for the Navy. Its Special Activities Branch offered critical intelligence on German
U-boat technology, operations, and tactics, which proved decisive in the
Battle of the Atlantic. ONI supplied U.S. forces with ship and aircraft recognition manuals, provided photographic specialists for identifying enemy vessels, assisted in naval mission planning, and was responsible for the
translation, evaluation, and dissemination of intercepted Japanese communications. In 1946, the Operational Intelligence Section was formed to provide fleet commanders with real-time analysis of the maritime activities and positions of foreign naval forces, namely the
Soviet Navy. The Navy Field Operational Intelligence Office (NFOIO) was established in 1957 to provide more advanced
signals intelligence and timely information on the intent of enemy forces. ONI also made a concerted effort to enhance its technical and scientific resources, diversifying its personnel to reflect a wider range of expertise. The Navy Scientific and Technical Intelligence Center (NAVSTIC) was established in 1968 and shortly thereafter was folded into the Navy Reconnaissance and Technical Support Center (NRTSC). In response to the threat posed by nuclear-armed Soviet submarines, ONI developed the Sound Surveillance System (SOSUS) and the Ocean Surveillance Information system (OSIS), allowing the U.S. Navy to monitor and deter these threats.
Consolidation and transformation Beginning in 1988, and following the
dissolution of the Soviet Union, ONI's headquarters was moved to its current location in the
National Maritime Intelligence Center (NMIC) in
Suitland, Maryland. It was joined by
Coast Guard Intelligence (CGI), which is responsible for domestic maritime operations, and the
Marine Corps Intelligence Activity, which supports expeditionary missions in
Littoral zones. The housing of all three of the nation's principal maritime intelligence agencies together was intended to facilitate
data sharing and coordination. ONI's duties and functions grew after the
September 11 terrorist attacks in 2001 and the subsequent role played by the U.S. Navy in related conflicts in Afghanistan, Iraq, and the Horn of Africa. The year 2009 was characterized by a major reorganization of the office. Chief of Naval Operations Admiral
Gary Roughead authorized ONI's conversion into a
command with four subordinate commands, each with a specialized function: scientific and technical intelligence, operational intelligence, information services and technology, and expeditionary and special warfare support. All four commands were collocated in NMIC, which was afterward designated by the
Director of National Intelligence as the nation's central source for integrated strategic maritime intelligence. The same year, the Information Dominance Corps (IDC) was established by the Navy to train enlisted sailors and officers in a wide range of supporting intelligence capabilities. The IDC was redesignated in 2016 as the
Information Warfare Community (IWC), with a greater emphasis on inter-disciplinary expertise in sustaining the U.S. Navy's operational and technological superiority. ONI provides the IWC with critical maritime intelligence and real-time global maritime surveillance. The 21st century has also seen an extension of ONI's support beyond the Navy and U.S. government and towards relevant academic and commercial partners. In addition to counter-terrorist activities, its concerns include
anti-piracy efforts, surveillance of potential maritime conflict zones (such as the
territorial disputes in the South China Sea), and monitoring the activities and developments in emerging rival navies (such as those of China, Russia, and Iran). ==Organization and personnel==