Where the Atomic Age Began: Manhattan Project National Historical Park

One of America’s newest national parks, Manhattan Project National Historical Park, is an intriguingly unique place that tells the story of the people, events, and science that led to the creation of the atomic bomb, brought an end to World War II, and ushered in the atomic era. 

Dawn of the Atomic Age

Physicists Albert Einstein and Leo Szilard

The Manhattan Project was an unprecedented, secret program implemented by the United States during World War II. The goal was to design and construct the world’s first atomic bomb. No one knew for sure if this could even be done, but Germany’s discovery of nuclear fission in 1938 made one thing clear: If the possibility did exist, it was imperative that the U.S. develop the bomb before Germany did. 

President Franklin D. Roosevelt granted federal funding for uranium research in 1939, shortly after receiving a fearful letter from Albert Einstein, who warned of the potential for an "extremely powerful bomb." By 1942, U.S. scientists concluded that developing an atomic bomb was indeed possible, but were divided over whether the path to its creation lay in the uranium-235 isotope, which makes up a tiny fraction of naturally occurring uranium, or in the newly discovered element plutonium, which was created in a controlled chain reaction using uranium.

Three unique facilities

From 1942 to 1945, scientists pursued both options, carrying out testing and research at three unique, top-secret locations in far-flung corners of the country. 

  • Oak Ridge, Tennessee: The enrichment of uranium — a process necessary to create plutonium — took place at an enormous industrial complex in Oak Ridge, Tennessee. This newly built facility also included a pilot reactor and chemical separation plant to create and purify the plutonium. 

Entrance to Oak Ridge labs
  • Hanford, Washington: A second complex similar to the Oak Ridge facility was constructed in Hanford, Washington, which included chemical separation plants and huge, production-scale reactors. Progress at both sites was slow and difficult, and the sufficient amount of uranium-235 and plutonium needed to build the bomb did not become readily available until mid-1945.

Nuclear production complex
  • Los Alamos, New Mexico: The actual construction of the atomic bomb took place at an isolated bomb design and development laboratory in Los Alamos, New Mexico, under the leadership of J. Robert Oppenheimer. Once the lab was complete, nuclear testing took place at the Trinity testing site, located about 220 miles from Los Alamos, on July 16, 1945.

Nuclear testing took place at the Trinity testing site

All three of these distinct sites make Manhattan Project National Historical Park one of a kind in our National Park System.

Visiting your new national park

While the Oak Ridge, Hanford, and Los Alamos sites are all included in this new national park, public access to the three areas varies due to continuing development and ongoing work by the U.S. Department of Energy.

Each of the three units includes different must see features and places to go. Experience a guided tour of the B Reactor National Historic Landmark in Hanford where all the material for the initial Trinity test was produced, or visit the Oak Ridge Reservation for a bus tour that includes the X-10 Graphite Reactor (the pilot nuclear reactor for the Manhattan Project) and the East Tennessee Technology Park (where uranium enrichment was pioneered). Walking tours are also available in downtown Los Alamos to visit the sites and facilities where actual bombs were designed and assembled.

Manhattan Project National Historical Park represents a complex chapter in our history, one that includes some of the most compelling stories and scientific achievements of the 20th century. Be one of the first to visit this extraordinary new park and share your experience with us on Facebook, Twitter, Instagram, and Tumblr.

Photo credits: Department of Energy and Wikimedia Common



Hello, my daughter and I will be visiting the Hanford site in October as part of a homeschool field trip. My father, Martin Zizzi is one of the docents giving the tour. Are there any books/resources you can reccomend for school children in the grades of 2-5 that cover this material??Thank you!

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