Underground Nuclear Detonations

This document lists chronologically and alphabetically by name all nuclear tests and simultaneous detonations conducted by the United States from July 1945 through September 1992. Two nuclear weapons that the United States exploded over Japan ending World War II are not listed. These detonations were not "tests" in the sense that they were conducted to prove that the weapon would work as designed (as was the first test near Alamogordo, New Mexico on July 16, 1945), or to advance nuclear weapon design, or to determine weapons effects, or to verify weapon safety as were the more than one thousand tests that have taken place since June 30,1946. The nuclear weapon (nicknamed "Little Boy") dropped August 6,1945 from a United States Army Air Force B-29 bomber (the Enola Gay) and detonated over Hiroshima, Japan had an energy yield equivalent to that of 15,000 tons of TNT. The nuclear weapon (virtually identical to "Fat Man") exploded in a similar fashion August 9, 1945 over Nagaski, Japan had a yield of 21,000 tons of TNT. Both detonations were intended to end World War II as quickly as possible. Data on United States tests were obtained from, and verified by, the U.S. Department of Energy's three weapons laboratories -- Los Alamos National Laboratory, Los Alamos, New Mexico; Lawrence Livermore National Laboratory, Livermore, California; and Sandia National Laboratories, Albuquerque, New Mexico; and the Defense Threat Reduction Agency. Additionally, data were obtained from public announcements issued by the U.S. Atomic Energy Commission and its successors, the U.S. Energy Research and Development Administration, and the U.S. Department of Energy, respectively.