List of nuclear weapons tests of the United States



As part of the nuclear arms race, the United States conducted around 1,054 nuclear tests (by official count) between 1945 and 1992, including 216 atmospheric, underwater, and space tests. Most of the tests took place at the Nevada Test Site and the Pacific Proving Grounds in the Marshall Islands and off Kiribati Island in the Pacific, plus three in the Atlantic Ocean. Ten other tests took place at various locations in the United States, including Alaska, Nevada other than the NNSS/NTS, Colorado, Mississippi, and New Mexico.

Testing Moratorium of 1959–1960
A voluntary moratorium terminates all nuclear testing for the US along with the Soviet Union and the United Kingdom. The moratorium is broken by France, becoming the fourth nuclear state with its test, "Gerboise Bleue", on February 13, 1960. The Soviet Union responds by breaking the moratorium on September 1st by resuming testing (including the 50 Mt "Tsar Bomba" device on October 30, 1961) and the US joins in breaking the moritorium by resuming weapons testing on 15 September 1961.

1961–1963
After the signing of the Partial Test Ban Treaty in 1963, all U.S. nuclear testing became underground testing.

1964–1992
A number of shots whose goals were to assess the non-military use of nuclear weapons were known as Operation Plowshare, and done during many different test series.

The United States has not conducted any tests since 1992, though they have conducted a number of sub-critical tests (which do not involve a chain reaction).

The United States has signed, but not ratified the Comprehensive Nuclear Test Ban Treaty.