Nowhere. The first atomic bomb was made in Los Alamos, New Mexico.
However uranium was enriched in several large plants at Oak Ridge, Tennessee. This site was selected by the Manhattan Project due to the available of low cost electricity from the Tennessee Valley Authority, which was needed to operate the thousands of pumps in the Gaseous Diffusion enrichment process.
This uranium was used in the Little Boy bomb (the second atomic bomb detonated, the first atomic bomb used in combat) and at low enrichment levels in the Hanford plutonium production reactor's fuel.
The nuclear material used to make the bombs was from Oak Ridge TN
US
1945
it was first noticed with the nuclear bomb tests.
No one. The first nuclear device was not tested until July of 1945, and the first bomb was not produced (not used) until later that month.
The first was made in the US. The purpose was originally to defend against the possibility of a Nazi bomb. 1945.
Germany has not made a nuclear bomb.
Atom bomb dropped in Japan by the U.S. during WWII
No one person made any nuclear bomb. Different components were/are made by different people, then a team of a dozen or more do final assembly.
I think it was Arizona Actually the nuclear bomb called the Manhattan Project was made and tested in New Mexico.
Long before the first one was made. That was the purpose of making them: to have a very dangerous bomb (all bombs are dangerous).
United States.