Where were the two times nuclear weapons were used in the past?

1. August 6, 1945: Hiroshima MK-I (Little Boy) Uranium gun mechanism
2. August 9, 1945: Nagasaki MK-III (Fat Man) Plutonium implosion mechanism

21 more bombs of the MK-III type were scheduled for production in 1945, one of which was completed 4 days after the Japanese surrender and so was not used (it probably became the first atomic bomb in the US stockpile).