You are here

Students arrive at B Reactor for a tour. The Department of Energy works with elementary, middle, and high schools around the region to highlight B Reactor’s role in ushering in the atomic age, and the importance of STEM education.
This 2016 photo shows a view of the Hanford Site's B Reactor National Historic Landmark, a vibrant tourism and education draw that is part of the Manhattan Project National Historical Park.

The Manhattan Project was an unprecedented, top-secret research and development program created during World War II to develop an atomic weapon.

The beginning of the atomic age is recognized as one of the most important events of the 20th century. Its profound legacies include the proliferation of nuclear weapons, vast environmental remediation efforts, the development of the national laboratory system, and peaceful uses of nuclear materials such as nuclear medicine.

In 2001, DOE worked with the Advisory Council on Historic Preservation and a panel of distinguished historic preservation experts to develop preservation options for six DOE-owned Manhattan Project-era historic facilities that the panel found to be of extraordinary historical significance and worthy of “commemoration as national treasures.”

In 2004, Congress directed the National Park Service (NPS) to work with DOE to evaluate whether it was appropriate and feasible to establish a new unit of the national park system dedicated to telling the story of the Manhattan Project.

After a decade of work by local communities, elected officials, DOE, NPS, and other stakeholders, the Manhattan Project National Historical Park was authorized as part of the Carl Levin and Howard P. “Buck” McKeon National Defense Authorization Act for Fiscal Year 2015. The park includes facilities at the three primary Manhattan Project locations — Los Alamos, Oak Ridge, and Hanford.

At Los Alamos, more than 6,000 scientists and support personnel worked to design and build the atomic weapons. The park currently includes three areas there: Gun Site, which was associated with the design of the “Little Boy” bomb; V-Site, which was used to assemble components of the Trinity device; and Pajarito Site, which was used for plutonium chemistry research.

A view of the grand opening of the K-25 History Center at Oak Ridge in February 2020. The K-25 footprint is part of the Manhattan Project National Historical Park.
A view of the grand opening of the K-25 History Center at Oak Ridge in February 2020. The K-25 footprint is part of the Manhattan Project National Historical Park.

The Clinton Engineer Works, which became the Oak Ridge Reservation, supported three parallel industrial processes for uranium enrichment and experimental plutonium production.

The park includes the X-10 Graphite Reactor National Historic Landmark, which produced small quantities of plutonium to support Los Alamos weapons work; buildings at the Y-12 complex, home to the electromagnetic separation process for uranium enrichment; and the site of the K-25 building, where gaseous diffusion uranium enrichment technology was pioneered.

The Hanford Engineer Works, now the Hanford Site, was home to more than 51,000 workers who constructed and operated a massive industrial complex to fabricate, test, and irradiate uranium fuel in reactors and then chemically separate out plutonium to be used in weapons.

The Hanford landscape is also representative of one of the first acts of the Manhattan Project — the condemnation of private property and eviction of homeowners and American Indian tribes to clear the way for the top-secret work. The park includes the B Reactor National Historic Landmark, which produced the material for the Trinity Test and plutonium bomb; and four turn-of-the-century historic buildings that give visitors a glimpse into the history of the Hanford area before the arrival of the Manhattan Project.

The park is managed as a collaborative partnership between DOE, which continues to own, preserve, and maintain the park facilities and will work to expand public access to them; and NPS, which administers the park, interprets the story of the Manhattan Project, and provides technical assistance to DOE on historic preservation. A memorandum of agreement between DOE and the U.S. Department of the Interior signed in November 2015 officially created the park and guides implementation of the park mission by the two agencies.

In this 2018 photo, visitors to the Pajarito Site at Los Alamos learn about Manhattan Project history. The site includes the Pond Cabin, Battleship Bunker, and Slotin Building used by scientists developing the plutonium bomb.
In this 2018 photo, visitors to the Pajarito Site at Los Alamos learn about Manhattan Project history. The site includes the Pond Cabin, Battleship Bunker, and Slotin Building used by scientists developing the plutonium bomb.

While a key component of the national historical park mission within DOE is enhancing public access to the park facilities, DOE and its contractors are also working to develop online resources so virtual visitors and students can learn about the historic facilities and the Manhattan Project.

This DOE webpage offers a wide range of in-print, online, and in-person Manhattan Project historical resources. The Department also produced podcasts on the history and impact of the Manhattan Project.

At the Los Alamos park unit, the Bradbury Science Museum, operated by Los Alamos National Laboratory, provides numerous electronic resources, including an overview of the park and Project Y in Los Alamos, and an overview of Manhattan Project sites on laboratory land. The Bradbury Science Museum’s online collections database allows visitors to search artifacts, photos, and historic documents from the Manhattan Project. LANL has also produced a video of historic sites and work to preserve them for future generations.

DOE, in partnership with a local biking club and the National Park Service, has sponsored an annual bike ride around the B Reactor at the Hanford Site, as shown here in this 2016 photo.
DOE, in partnership with a local biking club and the National Park Service, has sponsored an annual bike ride around the B Reactor at the Hanford Site, as shown here in this 2016 photo.

Oak Ridge's K-25 Virtual Museum offers visitors information about the Manhattan Project and Cold war.

The Hanford park unit is accessible to virtual visitors through a variety of resources, including those provided by partners in the community. DOE offers virtual access to the B Reactor National Historic Landmark via a 360-degree camera system.

The Hanford History Project (HHP) at Washington State University Tri Cities preserves DOE’s federal Manhattan Project and Cold War collection of artifacts and oral histories. Virtual access to these collections, as well as the HHP’s collections of oral histories, donated archive materials, documents, and photographs are available at HHP’s website.

The B Reactor Museum Association provides a series of videos with in-depth information on how the B Reactor functions and why it is recognized as a scientific and engineering marvel.

NPS maintains the official park webpage.

Email Updates
To receive the latest news and updates about the Office of Environmental Management, submit your e-mail address