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United States of America
Main article: List of nuclear weapons tests of the United States
The United States conducted around 1,054 nuclear tests (by official count) between 1945 and 1992. Some significant tests conducted by the United States include:[1]

Shot "Baker" of Operation Crossroads (1946) was the first underwater nuclear explosion.
The "Trinity" test on 16 July 1945, was the first-ever test of a nuclear weapon (yield of around 20 kt).
The Operation Crossroads series in July 1946, was the first postwar test series and one of the largest military operations in U.S. history.
The Operation Greenhouse shots of May 1951 included the first boosted fission weapon test ("Item") and a scientific test which proved the feasibility of thermonuclear weapons ("George").
The "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.
The "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 U.S. 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 Islands natives have since suffered from birth defects and have received some compensation from the federal government. A Japanese fishing boat, the Fifth Lucky Dragon, 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 200 kilometers' altitude during a series of high altitude nuclear explosions.
Shot "Frigate Bird" of Operation Dominic I on 6 May 1962, was the only U.S. test of an operational ballistic missile with a live nuclear warhead (yield of 600 kilotons), at Christmas Kiritimati Island in the Pacific. 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 missile was only a SLBM (and not an ICBM), so by itself it did not satisfy all concerns.[2]
Shot "Sedan" of Operation Storax on 6 July 1962 (yield of 104 kilotons), was an attempt at showing the feasibility of using nuclear weapons for "civilian" and "peaceful" purposes as part of Operation Plowshare. In this instance, a 1280-feet-in-diameter and 320-feet-deep crater was created at the Nevada Test Site.
Source:  Wikipedia   NOTE: There were no other references to North American sites.