Nuclear weapons of the United States

The United States was the first country to manufacture nuclear weapons and is the only country to have used them in combat, with the bombings of Hiroshima and Nagasaki in World War II against Japan. Before and during the Cold War, it conducted 1,054 nuclear tests, and tested many long-range nuclear weapons delivery systems.

Between 1940 and 1996, the U.S. federal government spent at least US$11.7 trillion in present-day terms on nuclear weapons, including platforms development (aircraft, rockets and facilities), command and control, maintenance, waste management and administrative costs. It is estimated that the United States produced more than 70,000 nuclear warheads since 1945, more than all other nuclear weapon states combined. Until November 1962, the vast majority of U.S. nuclear tests were above ground. After the 1963 Partial Nuclear Test Ban Treaty, all testing was relegated underground, in order to prevent the dispersion of nuclear fallout. The United States has maintained a unilateral moratorium on nuclear explosive testing since 1992 and signed the Comprehensive Nuclear-Test-Ban Treaty in 1996. The Science-Based Stockpile Stewardship program shifted focus from continual weapon redesigns to understanding and limiting aging. Research continues via supercomputer simulation and nuclear physics experiments.

By 1998, at least US$759 million had been paid to the Marshall Islanders in compensation for their exposure to U.S. nuclear testing. By March 2021 over US$2.5 billion in compensation had been paid to U.S. citizens exposed to nuclear hazards as a result of the U.S. nuclear weapons program.

In 2019, the U.S. and Russia possessed a comparable number of nuclear warheads; together, these two nations possess more than 90% of the world's nuclear weapons stockpile. In 2025, it was estimated that the United States held 1,770 deployed warheads, 1,930 in reserve, and 1,477 retired and awaiting dismantlement, in total 5,177 nuclear warheads. The projected costs for maintaining U.S. nuclear forces are $60 billion per year during the 2021–2030 period.