New National Park to Commemorate Manhattan Project
For more than a decade, the Department of the Interior and the Department of Energy have collaborated to create a new national park that chronicles the stories of people, events, science, and engineering behind the Manhattan Project.

With the hope of developing technology that would end World War II, the U.S. government organized this unprecedented top-secret project to produce the world’s first atomic weapons. For years, tens of thousands of people worked in facilities located in three cities: Oak Ridge, Tennessee; Hanford, Washington; and Los Alamos, New Mexico.

The Manhattan Project National Historical Park consists of these three locations in an effort to preserve the sites, facilities, equipment, and artifacts associated with this classified mission that changed the world forever. Read more.

Manhattan Project National Historical Park’s Oak Ridge Site (Watch Video)

August, 1939

A letter to the President
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December, 1941

The Japanese attack Pearl Harbor
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September, 1942

"Site X" is approved in East Tennessee
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November, 1942

"Site Y" is designated in Los Alamos, New Mexico
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January, 1943

"Site W" is chosen in southern Washington
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February, 1943

X-10 reactor and Y-12 plant
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April, 1943

Bomb design begins at Los Alamos site
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July, 1943

Manhattan Project sites proclaimed military districts
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November, 1943

X-10 reactor in Oak Ridge reaches criticality
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February, 1944

First enriched U-235 is delivered to Los Alamos
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September, 1944

Hanford's Reactor B goes critical
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February, 1945

Hanford delivers plutonium-239 to Los Alamos
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May, 1945

European theater of WW2 ends
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July, 1945

Test device detonated near Alamogordo, NM
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August, 1945

Atomic bombs are dropped on Japan
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September, 1945

Japan surrenders to the Allies
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January, 1948

Atomic Energy Act goes into effect
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November, 2015

Establishment of Manhattan Project National Historical Park
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