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All testing was voluntarily terminated in 1958, leading to Partial Test Ban Treaty in 1963

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.[1] 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.


Year Series No. shots Total yields Location(s) Image Notes
1945 Trinity 1 20 kt Alamogordo, New Mexico The "Trinity" fireball First ever nuclear explosion.
1946 Crossroads 2 46 kt Pacific Proving Grounds "Baker" shot First postwar test series. First underwater nuclear explosion.
1948 Sandstone 3 104 kt Pacific Proving Grounds Shot "X-Ray" of Operation Sandstone. The first use of "levitated" cores. Developed the Mark IV warhead.
1951 Ranger 5 40 kt Nevada Test Site Shot "Fox" of Operation Ranger. First tests at the Nevada Test Site.
1951 Greenhouse 4 398.5 kt Pacific Proving Grounds The "Item" fireball. "George" shot was physics experiment relating to the hydrogen bomb; "Item" shot was first boosted fission weapon.
1951 Buster-Jangle 7 71.9 kt Nevada Test Site Troops during the "Buster Dog" shot. Many shots done in conjunction with troop exercises on ground.
1952 Tumbler-Snapper 7 104 kt Nevada Test Site A "Snapper" shot shows the "rope trick effect". Operation "Snapper" tested a number of new devices, and also explored the "rope trick effect".
1952 Ivy 2 10.9 Mt Pacific Proving Grounds The "Mike" mushroom cloud. "Mike" shot was first hydrogen bomb; "King" shot was largest pure-fission bomb (500 kt).
1953 Upshot-Knothole 11 252.4 kt Nevada Test Site Shot "Grable" and the "atomic cannon". Grable shot used a 280mm M65 Atomic cannon.
1954 Castle 6 48.2 Mt Pacific Proving Grounds The "Romeo" mushroom cloud. Deployable thermonuclears. "Bravo" was over twice as large as expected (most powerful ever by U.S.) and spread fallout over a wide area. Hydrogen bombs that used cryogenic fuel were obsolete.
1955 Teapot 14 167.8 kt Nevada Test Site The "Tesla" fireball. First successful designs by Lawrence Livermore National Laboratory (after two years of trying).
1955 Wigwam 1 30 kt Pacific Ocean The "Wigwam" detonation. A single shot, 2000 ft underwater, to determine the vulnerability of submarines to nuclear explosions.
1955-56 Project 56 4 .01 to .1 kt Nevada Test Site Four 'one-point' safety tests, to ensure the safety of deployed designs.
1956 Redwing 17 20.82 Mt Pacific Proving Grounds The "Apache" detonation. All thermonuclear weapons designs tests, including first "three stage" weapon test.
1957 Project 57 1 0 t Nellis Air Force Range One 'one-point' safety test, to ensure the safety of deployed designs.
1957 Plumbbob 29 343.74 kt Nevada Test Site Shot "Smoky" of Operation Plumbbob. One of the most controversial test series, release more radiation to continental U.S. than any series. Close proximity of troop exercises to shot "Smoky" produced significantly increased levels of leukemia among exposed soldiers.[citation needed]
1957–58 Project 58, Project 58A 4 0.5 kt Nevada Test Site Four 'one-point' safety tests, to ensure the safety of deployed designs.
1958 Chariot Cancelled Cape Thompson, Alaska The plans to use five thermonuclear explosions to create an artificial harbor in Alaska Had planned to create an artificial harbor in Alaska as part of Operation Plowshare using thermonuclear explosions. Was eventually canceled amid controversy.
1958 Operation Hardtack I 35 35.6 Mt Pacific Proving Grounds Shot "Oak" of Operation Hardtack I First live nuclear bomb launched by a missile (U.S. Army's PGM-11 Redstone)
1958 Argus 3 5.1 kt South Atlantic Ocean Clandestine high-altitude test series carried out 1,110 miles southwest of South Africa to test whether nuclear explosions could create artificial Van Allen belts in near space.
1958 Operation Hardtack II 37 45.8 kt Nevada Test Site Shot "Sorocco" of Operation Hardtack II.

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 1 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.


Year Series No. shots Total yields Location(s) Image Notes
1961–62 Nougat 32 Nevada Test Site, Carlsbad, New Mexico The underground cavity created by the "Gnome" shot. First all-underground test series. Included Operation Plowshare shot "Gnome" in Carlsbad, New Mexico, which was detonated in an underground salt dome.
1962–63 Dominic 36 38.1 Mt Christmas Island, Johnston Island, Central Pacific Ocean "Starfish-Prime" in the upper atmosphere. "Frigate Bird" was the only operational test of a missile "mated" with a live warhead. Series also included three high-altitude tests known as Operation Fishbowl.
1962–63 Storax 48 Nevada Test Site The "Sedan" crater. Included the "Sedan" test, a cratering experiment as part of Operation Plowshare.
1962 Sunbeam 4 2.19 kt Nevada Test Site The 1.65 kt "Small Boy" nuclear test of 1962. Test of small tactical warheads, including the man-portable "Davy Crockett". Last atmospheric test series.
1963 Roller Coaster 4 0 Nellis Air Force Range, Nevada Storage-transportation safety experiment, measured plutonium dispersal risk.

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


Year Series No. shots Total yields Location(s) Notes
1964–65 Niblick 41 Nevada Test Site, Fallon, Nevada
1964–65 Whetstone 48 Nevada Test Site, Hattiesburg, Mississippi
1965–66 Flintlock 48 Nevada Test Site, Amchitka, Alaska
1966–67 Latchkey 38 Nevada Test Site, Hattiesburg, Mississippi
1967–68 Crosstie 48 Nevada Test Site, Farmington, New Mexico, Hot Creek Valley, Nevada Included "Gasbuggy" Plowshare shot near Farmington, New Mexico and "Faultless" shot in Nevada's Hot Creek valley.
1968–69 Bowline 48 Nevada Test Site
1969 Mandrel 53 Nevada Test Site; Grand Valley, Colorado; Amchitka, Alaska Included "Rulison" Plowshare shot near Grand Valley, Colorado, and 1.2 Mt shot "Milrow" in Alaska.
1970 Emery 16 Nevada Test Site
1971–72 Grommet 34 Nevada Test Site, Amchitka, Alaska Included largest US underground detonation, the > 5 Mt shot "Cannikin" (for the Spartan Missile warhead) in Alaska.
1972–73 Toggle 28 Nevada Test Site, Rifle, Colorado Included Plowshare "Rio Blanco" test for gas stimulation
1973–74 Arbor 19 Nevada Test Site
1974–75 Bedrock 27 Nevada Test Site
1975–76 Anvil 21 Nevada Test Site
1976–77 Fulcrum 21 Nevada Test Site All "weapons related" tests.
1977–78 Cresset 23 Nevada Test Site
1978–79 Quicksilver 18 Nevada Test Site
1979–80 Tinderbox 15 Nevada Test Site
1980–81 Guardian 16 Nevada Test Site
1981–82 Praetorian 22 Nevada Test Site
1982–83 Phalanx 19 Nevada Test Site
1983–84 Fusileer 17 Nevada Test Site
1984–85 Grenadier 17 Nevada Test Site
1985–86 Charioteer 18 Nevada Test Site Mighty Oak test using the Mk-21 RV warhead. was conducted on April 10, 1986. Containment failed and later radiation was released. Secondary sources put this venting into at 36,000 curies, which is 2000 times greater than the 3 Mile Island incident. Sources: Dr. Rosalie Bertell, Dr. Bonnie Eberhardt, journalist Paul Van Dam.
1986–87 Musketeer 15 Nevada Test Site
1987–88 Touchstone 14 Nevada Test Site
1988–89 Cornerstone 12 Nevada Test Site
1989–90 Aqueduct 11 Nevada Test Site
1990–91 Sculpin 8 Nevada Test Site
1991–92 Julin 8 <460kt Nevada Test Site Last nuclear test series. Last shot was "Divider" (September 23, 1992). Exact yields not released.

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.


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