Atoll with about 20 islets (pop. 1999: 13), Marshall Islands , Micronesia .
It was administered by the U.S. from 1947 as part of the U.S. Trust Territory of the Pacific Islands under a UN trusteeship. The U.S. used the atoll for atomic testing 1946–58. The 167 inhabitants were removed before the tests began and returned in 1969, but they were evacuated again in 1978 because of high radiation levels. Cleanup there continued, and in 1997 Bikini was pronounced safe for habitation. The atoll became part of the Republic of the Marshall Islands in 1979.