Where was the first atom bomb dropped?

The first nuclear bomb was dropped on Hiroshima, Japan on 6 August 1945. this was the gun-type weapon codenamed Little Boy. Three days later, 9 August 1945, the third nuclear detonation in history occurred over Nagasaki, Japan, with the dropping of the implosion type device, Fat Man.

The first nuclear detonation in history occurred at the Trinity test site outside Alamogordo, New Mexico on 16 July 1945.