U.S. Nuclear Stockpile: 3,700 Warheads, 1,477 Awaiting Dismantlement

Atmospheric – 15 Mt(1 March 1954) Underground – 5 megatons of TNT (21 PJ)(6 November 1971) U.S. Navy Ohio-class submarines Trident-II ballistic missiles Ohio-class submarines Trident-II ballistic missiles Trident-II ballistic missiles U.S. Air Force Minuteman-III intercontinental ballistic missiles B-52H Stratofortress bombers AGM-86B cruise missiles B-2A Spirit bombers B61 bombs B83 bombs[a] Minuteman-III intercontinental ballistic missiles B-52H Stratofortress bombers AGM-86B cruise missiles B-2A Spirit bombers B61 bombs B83 bombs[a] U.S. Air Force Dual Capable Aircraft B61 bombs Dual Capable Aircraft B61 bombs The United States holds the second largest arsenal of nuclear weapons among the nine nuclear-armed countries. Under the Manhattan Project, the United States became the first country to manufacture nuclear weapons and remains the only country to have used them in combat, with the bombings of Hiroshima and Nagasaki in World War II against Japan. In total it conducted 1,054 nuclear tests, the most of any country.[b] It is an original party to and one of the five "nuclear-weapon states" recognized by the 1968 Treaty on the Non-Proliferation of Nuclear Weapons. As of 2025[update], the US and Russia possess a comparable number of warheads; together more than 90% of the world's stockpile.[7][8] The US holds in total 5,177 warheads, of which 3,700 are stockpiled, and 1,477 are awaiting dismantlement. Of the stockpile, 1,770 are deployed, while 1,930 are held in reserve.[9] The president of the United States has the sole authority to use nuclear weapons. US policy permits nuclear first use, and as of 2024[update] aims to "deter Russia, the PRC, and the DPRK simultaneously".[10] The US stockpile is mostly under Strategic Command,[c] assigned to its nuclear triad: 1,920[d] to 280 Trident II submarine-launched ballistic missiles aboard 14 Ohio-class submarines, 800[e] to 400 silo-based Minuteman III intercontinental ballistic missiles, and 780[f] B61 and B83[a] bombs and AGM-86B cruise missiles to 19 B-2 Spirit and 46 B-52 Stratofortress bombers respectively. The US plans to modernize its triad with the Columbia-class submarine, Sentinel ICBM, and B-21 Raider, from 2029.[11] Early warning is provided by radars including Solid State Phased Arrays and satellites including the Space-Based Infrared System. The Missile Defense Agency coordinates the US anti-ballistic missile network: the Ground-Based Interceptor, Aegis, Terminal High Altitude Area Defense, and MIM-104 Patriot systems. Additionally, 200 B61 nuclear bombs are available for tactical nuclear use by fighter aircraft.[g] The US stations approximately 100 of these in six European NATO countries: Belgium, Germany, Italy, the Netherlands, Turkey, and United Kingdom. The US extends a nuclear umbrella to all NATO countries, and also South Korea, Japan, and Australia. Since the 2014 Russian annexation of Crimea, the US has more frequently moved strategic nuclear delivery systems to the territory of its allies, with Bomber Task Force deployments in Australia, Qatar, Romania, and South Korea,[12][13] while Ohio-class submarines have docked in Scotland and South Korea.[12] Throughout the Cold War, the US and USSR competed in the nuclear arms race. From 1951, the US became the first country to develop thermonuclear weapons. From the 1950s, the US stationed nuclear weapons in at least 17 other nations, including NATO allies, South Korea, Japan, Taiwan, and the Philippines, while Strategic Air Command operated hundreds of strategic bombers, under the policies of massive retaliation and containment of Eastern Bloc countries. By the 1960s, ICBMs were deployed in silos, such as the Atlas and Titan, and aboard submarines as Polaris, with the arsenal peaking at 31,000 warheads in 1967.[14] The 1962 Cuban Missile Crisis is regarded as a nuclear close call that cemented the concept of mutually assured destruction. Technologies advanced in the 1980s, with the Peacekeeper ICBM and proposed space-based Strategic Defense Initiative missile defense system. When the Cold War ended, all Army and surface Navy nuclear weapons were withdrawn, and Strategic Air Command was superseded by Strategic Command. The arsenal was also limited by bilateral treaties, beginning with START I. Its successor, New START, expired in 2026. Since 2025, the US has pursued the space-based Golden Dome missile defense system. Between 1940 and 1996, the US spent over US$11.9 trillion in present-day terms[15] on nuclear weapons infrastructure,[16] and nuclear forces maintenance is projected to cost $60 billion per year from 2021 through 2030.[17] The US produced over 70,000 nuclear warheads, more than all other states combined.[18] Design takes place at Los Alamos, Livermore, and Sandia laboratories; tests were conducted at Nevada Test Site and Pacific Proving Grounds. Until the 1963 Partial Nuclear Test Ban Treaty, the vast majority of tests were atmospheric. Subsequent underground testing limited nuclear fallout.[19] Nuclear sites radioactively contaminated civilian communities: the US government compensated Marshall Islanders over US$759 million for testing exposure,[20][21] and US citizens over US$2.5 billion.[22] The US began a testing moratorium in 1992[23] and signed the Comprehensive Nuclear-Test-Ban Treaty in 1996, but has not ratified it. Stockpile stewardship is the current warhead maintenance program, using experiments including supercomputer simulation and inertial confinement fusion.[24] The United States first began developing nuclear weapons during World War II under the order of President Franklin Roosevelt in 1939, motivated by the fear that they were engaged in a race with Nazi Germany to develop such a weapon. After a slow start under the direction of the National Bureau of Standards, at the urging of British scientists and American administrators, the program was put under the Office of Scientific Research and Development, and in 1942 it was officially transferred under the auspices of the United States Army and became known as the Manhattan Project, an American, British and Canadian joint venture. Under the direction of General Leslie Groves, over thirty different sites were constructed for the research, production, and testing of components related to bomb-making. These included the Los Alamos National Laboratory at Los Alamos, New Mexico, under the direction of physicist Robert Oppenheimer, the Hanford plutonium production facility in Washington, and the Y-12 National Security Complex in Tennessee. By investing heavily in breeding plutonium in early nuclear reactors and in the electromagnetic and gaseous diffusion enrichment processes for the production of uranium-235, the United States was able to develop three usable weapons by mid-1945. The Trinity test was a plutonium implosion-design weapon tested on 16 July 1945, with around a 20 kiloton yield.[25] Faced with a planned invasion of the Japanese home islands scheduled to begin on 1 November 1945 and with Japan not surrendering, President Harry S. Truman ordered the atomic raids on Japan. On 6 August 1945, the US detonated a uranium-gun design bomb, Little Boy, over the Japanese city of Hiroshima with an energy of about 15 kilotons of TNT, killing approximately 70,000 people, among them 20,000 Japanese combatants and 20,000 Korean forced laborers, and destroying nearly 50,000 buildings (including the 2nd General Army and Fifth Division headquarters). Three days later, on 9 August, the US attacked Nagasaki using a plutonium implosion-design bomb, Fat Man, with the explosion equivalent to about 20 kilotons of TNT, destroying 60% of the city and killing approximately 35,000 people, among them 23,200–28,200 Japanese munitions workers, 2,000 Korean forced laborers, and 150 Japanese combatants.[26] On 1 January 1947, the Atomic Energy Act of 1946 (known as the McMahon Act) took effect, and the Manhattan Project was officially turned over to the United States Atomic Energy Commission (AEC).[27] On 15 August 1947, the Manhattan Project was abolished.[28] The American atomic stockpile was small and grew slowly in the immediate aftermath of World War II, and the size of that stockpile was a closely guarded secret.[29] However, there were forces that pushed the United States towards greatly increasing the size of the stockpile. Some of these were international in origin and focused on the increasing tensions of the Cold War, including the loss of China, the Soviet Union becoming an atomic power, and the onset of the Korean War.[30] And some of the forces were domestic – both the Truman administration and the Eisenhower administration wanted to rein in military spending and avoid budget deficits and inflation.[31] It was the perception that nuclear weapons gave more "bang for the buck" and thus were the most cost-efficient way to respond to the security threat the Soviet Union represented.[32] As a result, beginning in 1950 the AEC embarked on a massive expansion of its production facilities, an effort that would eventually be one of the largest US government construction projects ever to take place outside of wartime.[33] And this production would soon include the far more powerful hydrogen bomb, which the United States had decided to move forward with after an intense debate during 1949–50.[34] as well as much smaller tactical atomic weapons for battlefield use.[35] By 1990, the United States had produced more than 70,000 nuclear warheads, in over 65 different varieties, ranging in yield from around .01 kilotons (such as the man-portable Davy Crockett shell) to the 25 megaton B41 bomb.[20] Between 1940 and 1996, the US spent at least $11.9 trillion in present-day terms[15] on nuclear weapons development. Over half was spent on building delivery mechanisms for the weapon. $749 billion in present-day terms was spent on nuclear waste management and environmental remediation.[16] Richland, Washington was the first city established to support plutonium production at the nearby Hanford nuclear site, to power the American nuclear weapons arsenals. It produced plutonium for use in cold war atomic bombs.[36] Throughout the Cold War, the US and USSR threatened with all-out nuclear attack in case of war, regardless of whether it was a conventional or a nuclear clash.[37] US nuclear doctrine called for mutually assured destruction (MAD), which entailed a massive nuclear attack against strategic targets and major populations centers of the Soviet Union and its allies. The term "mutual assured destruction" was coined in 1962 by American strategist Donald Brennan.[38] MAD was implemented by deploying nuclear weapons simultaneously on three different types of weapons platforms.[39][40][41] After the 1989 end of the Cold War and the 1991 dissolution of the Soviet Union, the US nuclear program was heavily curtailed; halting its program of nuclear testing, ceasing its production of new nuclear weapons, and reducing its stockpile by half by the mid-1990s under President Bill Clinton. Many former nuclear facilities were closed, and their sites became targets of extensive environmental remediation. Efforts were redirected from weapons production to stockpile stewardship; attempting to predict the behavior of aging weapons without using full-scale nuclear testing. Increased funding was directed to anti-nuclear proliferation programs, such as helping the states of the former Soviet Union to eliminate their former nuclear sites and to assist Russia in their efforts to inventory and secure their inherited nuclear stockpile. By February 2006, over $1.2 billion had been paid under the Radiation Exposure Compensation Act (RECA) of 1990 to US citizens exposed to nuclear hazards as a result of the US nuclear weapons program, and by 1998 at least $759 million had been paid to the Marshall Islanders in compensation for their exposure to US nuclear testing. Over $15 million was paid to the Japanese government following the exposure of its citizens and food supply to nuclear fallout from the 1954 "Bravo" test.[20][21] In 1998, the country spent an estimated $35.1 billion on its nuclear weapons and weapons-related programs.[20] In the 2013 book Plutopia: Nuclear Families, Atomic Cities, and the Great Soviet and American Plutonium Disasters (Oxford), Kate Brown explores the health of affected citizens in the United States, and the "slow-motion disasters" that still threaten the environments where the plants are located. According to Brown, the plants at Hanford, over a period of four decades, released millions of curies of radioactive isotopes into the surrounding environment.[36] Brown says that most of this radioactive contamination over the years at Hanford were part of normal operations, but unforeseen accidents did occur and plant management kept this secret, as the pollution continued unabated. Even today, as pollution threats to health and the environment persist, the government keeps knowledge about the associated risks from the public.[36] During the presidency of George W. Bush, and especially after the 11 September terrorist attacks of 2001, rumors circulated in major news sources that the US was considering designing new nuclear weapons ("bunker-busting nukes") and resuming nuclear testing for reasons of stockpile stewardship. Republicans argued that small nuclear weapons appear more likely to be used than large nuclear weapons, and thus small nuclear weapons pose a more credible threat that has more of a deterrent effect against hostile behavior. Democrats counterargued that allowing the weapons could trigger an arms race.[42] In 2003, the Senate Armed Services Committee voted to repeal the 1993 Spratt-Furse ban on the development of small nuclear weapons. This change was part of the 2004 fiscal year defense authorization. The Bush administration wanted the repeal so that they could develop weapons to address the threat from North Korea. "Low-yield weapons" (those with one-third the force of the bomb that was dropped on Hiroshima in 1945) were permitted to be developed.[43] The Bush administration was unsuccessful in its goal to develop a guided low-yield nuclear weapon, however, in 2010 President Barack Obama began funding and development for what would become the B61-12, a smart guided low-yield nuclear bomb developed off of the B61 “dumb bomb”.[44] Statements by the US government in 2004 indicated that they planned to decrease the arsenal to around 5,500 total warheads by 2012.[45] Much of that reduction was already accomplished by January 2008.[46] Since the 2014 Russian annexation of Crimea, the US has more frequently forward-deployed strategic nuclear assets, with Bomber Task Force posted to Australia, Qatar, and Romania, while the Ohio-class has made port calls in Scotland and South Korea.[12] According to the Pentagon's June 2019 Doctrine for Joint Nuclear Operations,[47] "Integration of nuclear weapons employment with conventional and special operations forces is essential to the success of any mission or operation."[48] In 2024 it was estimated that the United States possessed 1,770 deployed nuclear warheads, 1,938 in reserve, and 1,336 retired and awaiting dismantlement (a total of 5,044). 1,370 strategic warheads were deployed on ballistic missiles, 300 at strategic bomber bases in the United States, and 100 tactical bombs at air bases in Europe.[49] Between 16 July 1945 and 23 September 1992, the United States maintained a program of vigorous nuclear testing, with the exception of a moratorium between November 1958 and September 1961. By official count, a total of 1,054 nuclear tests and two nuclear attacks were conducted, with over 100 of them taking place at sites in the Pacific Ocean, over 900 of them at the Nevada Test Site, and ten on miscellaneous sites in the United States (Alaska, Colorado, Mississippi, and New Mexico).[6] Until November 1962, the vast majority of the US tests were atmospheric (that is, above-ground); after the acceptance of the Partial Test Ban Treaty all testing was relegated underground, in order to prevent the dispersion of nuclear fallout.[50] In 1992 a new testing moratorium was initiated, which has been maintained through 2024.[51] The US program of atmospheric nuclear testing exposed a number of the population to the hazards of fallout. Estimating exact numbers, and the exact consequences, of people exposed has been medically very difficult, with the exception of the high exposures of Marshall Islanders and Japanese fishers in the case of the Castle Bravo incident in 1954. A number of groups of US citizens—especially farmers and inhabitants of cities downwind of the Nevada Test Site and US military workers at various tests—have sued for compensation and recognition of their exposure, many successfully. The passage of the Radiation Exposure Compensation Act of 1990 allowed for a systematic filing of compensation claims in relation to testing as well as those employed at nuclear weapons facilities. By June 2009 over $1.4 billion total has been given in compensation, with over $660 million going to "downwinders".[21] Prior to his meeting with CCP General Secretary Xi Jinping on October 30, 2025, President Trump, in a social media post, "instructed the Department of War [sic]" to resume testing nuclear weapons "on an equal basis."[52] On October 31, in an interview with 60 Minutes, Trump claimed Russia, China, Pakistan, and North Korea were carrying out covert nuclear tests. On November 3, Secretary of Energy Chris Wright stated that nuclear testing would not resume, and subcritical testing would continue.[53] A few notable US nuclear tests include: Trinity test on 16 July 1945, was the world's first test of a nuclear weapon (yield of around 20 kt). Operation Crossroads series in July 1946, was the first postwar test series and one of the largest military operations in US history. Operation Greenhouse shots of May 1951 included the first boosted fission weapon test ("Item") and a scientific test that proved the feasibility of thermonuclear weapons ("George"). Ivy Mike shot of 1 November 1952, was the first full test of a Teller-Ulam design "staged" hydrogen bomb, with a yield of 10 megatons. It was not a deployable weapon, however—with its full cryogenic equipment it weighed some 82 tons. Castle Bravo shot of 1 March 1954, was the first test of a deployable (solid fuel) thermonuclear weapon, and also (accidentally) the largest weapon ever tested by the United States (15 megatons). It was also the single largest US radiological accident in connection with nuclear testing. The unanticipated yield, and a change in the weather, resulted in nuclear fallout spreading eastward onto the inhabited Rongelap and Rongerik atolls, which were soon evacuated. Many of the Marshall Islanders have since suffered from birth defects and have received some compensation from the federal government. A Japanese fishing boat, Daigo Fukuryū Maru, also came into contact with the fallout, which caused many of the crew to grow ill; one eventually died. Shot Argus I of Operation Argus, on 27 August 1958, was the first detonation of a nuclear weapon in outer space when a 1.7-kiloton warhead was detonated at an altitude of 200 kilometres (120 mi) during a series of high altitude nuclear explosions. Shot Frigate Bird of Operation Dominic I on 6 May 1962, was the only US test of an operational submarine-launched ballistic missile (SLBM) with a live nuclear warhead (yield of 600 kilotons), at Christmas Island. In general, missile systems were tested without live warheads and warheads were tested separately for safety concerns. In the early 1960s, however, there mounted technical questions about how the systems would behave under combat conditions (when they were "mated", in military parlance), and this test was meant to dispel these concerns. However, the warhead had to be somewhat modified before its use, and the miss