when was the atom bomb dropped on hiroshima
Atomic bombings of Hiroshima and Nagasaki
By August 1945 , the Allies ' Manhattan Project had produced two types of atomic bomb , and the 509th Composite Group of the United States Army Air Forces ( USAAF ) was equipped with the specialized Silverplate version of the Boeing B - 29 Superfortress that could deliver them from Tinian in the Mariana Islands . Orders for atomic bombs to be used on four Japanese cities were issued on July 25 . On August 6 , the U.S. dropped a uranium gun - type ( Little Boy ) bomb on Hiroshima , and American President Harry S. Truman called for Japan 's surrender , warning it to `` expect a rain of ruin from the air , the like of which has never been seen on this earth . '' Three days later , on August 9 , a plutonium implosion - type ( Fat Man ) bomb was dropped on Nagasaki . Within the first two to four months following the bombings , the acute effects of the atomic bombings had killed 90,000 -- 146,000 people in Hiroshima and 39,000 -- 80,000 in Nagasaki ; roughly half of the deaths in each city occurred on the first day . During the following months , large numbers died from the effect of burns , radiation sickness , and other injuries , compounded by illness and malnutrition . In both cities , most of the dead were civilians , although Hiroshima had a sizable military garrison . 
By August 1945 , the Allies ' Manhattan Project had produced two types of atomic bomb , and the 509th Composite Group of the United States Army Air Forces ( USAAF ) was equipped with the specialized Silverplate version of the Boeing B - 29 Superfortress that could deliver them from Tinian in the Mariana Islands . Orders for atomic bombs to be used on four Japanese cities were issued on July 25 . On August 6 , the U.S. dropped a uranium gun - type ( Little Boy ) bomb on Hiroshima , and American President Harry S. Truman called for Japan 's surrender , warning it to `` expect a rain of ruin from the air , the like of which has never been seen on this earth . '' Three days later , on August 9 , a plutonium implosion - type ( Fat Man ) bomb was dropped on Nagasaki . Within the first two to four months following the bombings , the acute effects of the atomic bombings had killed 90,000 -- 146,000 people in Hiroshima and 39,000 -- 80,000 in Nagasaki ; roughly half of the deaths in each city occurred on the first day . During the following months , large numbers died from the effect of burns , radiation sickness , and other injuries , compounded by illness and malnutrition . In both cities , most of the dead were civilians , although Hiroshima had a sizable military garrison .
On August 6, 1945, the U.S. dropped a uranium gun-type (Little Boy) bomb on Hiroshima.
By August 1945 , the Allies ' Manhattan Project had produced two types of atomic bomb , and the 509th Composite Group of the United States Army Air Forces ( USAAF ) was equipped with the specialized Silverplate version of the Boeing B - 29 On August 6 , the U.S. dropped a uranium gun - type ( Little Boy ) bomb on Hiroshima , and American President Harry S. Truman called for Japan 's surrender , warning it to `` expect a rain of ruin from the air , the like of which has never been seen on this earth . ''