How many people worked on the Manhattan Project?

History hard Data from 1945

Guess before you scroll — the answer is below

Answer in people. Shorthand like 9m or 1.2bn works.

The answer

130,000 people

Roughly 130K.

About 130,000 people worked on the Manhattan Project, the overwhelming majority with no idea what they were building. Secrecy was maintained by compartmentalising the work so thoroughly that entire towns were built without appearing on maps.

Where this number comes from

Source U.S. Department of Energy, Manhattan Project history
Figure refers to 1945
Last checked
Unit people

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