Frequently Asked Questions

A man speaks on the telephone in an office with photos and a calendar on the wall.
Answering questions in Oak Ridge, 1944.


Like the Manhattan Project, Manhattan Project National Historical Park is complicated. The park is located in three states (NM, TN, and WA) and is co-managed with the Department of Energy. This website offers a lot of great trip planning information to make your trip planning easier. Please visit Plan Your Visit for helpful information to plan your visit to one or all three park locations. The frequently asked questions below focus on the questions that the media and other interested organizations frequently ask park staff. If you have additional questions about the park, please contact us.

FAQs about the Manhattan Project


The Manhattan Project was an unprecedented, top-secret World War II government program in which the United States rushed to develop and deploy the world’s first atomic weapons before Nazi Germany. The development of these atomic weapons ushered in the nuclear age. The use of the atomic bombs by the United States against Japan in August 1945 is one of the most important historical events of the 20th century. 

Scientists in Germany discovered fission in December 1938. Hungarian physicist Leo Szilard realized that nuclear chain reactions could be used to create new and extremely powerful atomic weapons. In August 1939, Szilard wrote a letter for Albert Einstein to sign and send to President Franklin D. Roosevelt warning that an "extremely powerful bomb" might be constructed. Fearing ongoing research and development by Nazi Germany, Roosevelt formed the Advisory Committee on Uranium, which met for the first time on October 21, 1939. 

The United States formally entered World War II after Imperial Japan bombed the US Naval base at Pearl Harbor, Hawai’i on December 7, 1941. With the US now at war, the Advisory Committee on Uranium concluded that an atomic bomb could be designed, built, and used in time to influence the outcome of the war. To accomplish this task, the Army Corps of Engineers established the Manhattan Engineer District, headed by Brigadier General Leslie Groves, in Manhattan, New York. 

Approved by President Franklin D. Roosevelt, the Manhattan Project was officially created on August 13, 1942. On January 1, 1947, a civilian federal agency, the Atomic Energy Commission, assumed control of all Manhattan Project operations and formally ended the Manhattan Project in August that same year.  

The Manhattan Project cost approximately $2 billion by 1945 (or over $30 billion in 2023 USD). This spending was funded though the War Powers Act of 1941.   

The first headquarters of the Manhattan Engineer District was located on the 18th floor of the headquarters of the North Atlantic Division of the Army Corps of Engineers in midtown Manhattan, New York. The Manhattan Project was named after this location. In August 1943, the Manhattan Project headquarters move to Oak Ridge, Tennessee.  

The Manhattan Project’s three main centers of operation were: Hanford, Washington; Los Alamos, New Mexico; and Oak Ridge, Tennessee. Numerous smaller sites including uranium milling and refining facilities, research universities, and uranium mines supporting the project were located across the US, Canada, and in the Democratic Republic of the Congo (formerly the Belgian Congo).  

The project was kept secret through compartmentalization of job responsibilities, controlling access to places and information, and implementation of a complex security apparatus. Nuclear secrecy began after the discovery of fission and before the Manhattan Project with some scientists self-censoring publication of information they considered “sensitive.”  

Work on the Manhattan Project was compartmentalized with very few people knowing the full scope of the project. Construction and trades workers were told nothing of the true purpose of the facilities they built. Technical workers signed the Espionage Act that made giving information that interfered with the success of the US Armed Forces punishable by death.  

Secrecy sometimes cut across the dinner table where many Manhattan Project workers could not tell their families what they were working on. Investigators performed background checks on workers who needed access to sensitive materials and gave security clearances only to vetted workers. The three project sites all required a security badge to enter. Workers were provided color-coded security badges that identified what technical areas they could enter.  

The Manhattan Project was one of the most transformative events of the 20th century, and the legacy is immense. Geopolitically, one of the biggest legacies of the project was the Cold War, which unofficially began after the Soviet Union’s first successful atomic test in 1949. The Manhattan Project ushered in a whole new world of scientific research, used not only for atomic bomb purposes but also for advancements in nuclear energy and in the medical field, to name a few.   

The Manhattan Project also raised ethical and moral questions among scientists and citizens alike—questions that continue to this day. More than 200,000 people died by the end of 1945 as a direct result of the atomic bombings. The advancement of nuclear science has given rise to nuclear energy and medicine as well as radioactive waste and health problems. The Manhattan Project and its legacies are as complex as the science that made the project possible. 


FAQs about Manhattan Project National Historical Park


Established on November 10, 2015, Manhattan Project National Historical Park preserves and interprets the nationally significant historic sites, stories, and legacies associated with the top-secret race to develop an atomic weapon during World War II, and provides access to these sites consistent with the mission of the Department of Energy. 

The park is located in three states: Hanford (Tri-Cities), Washington; Los Alamos, New Mexico; and Oak Ridge, Tennessee. 

There is a lot of great information on this website about the history, science, and legacies of the Manhattan Project.

The National Park Service mobile app is one of the best ways to learn about the park. The app features walking and driving tours, things to do, interactive maps, and more to enhance your in-person or virtual visit.   

The park is co-managed with the Department of Energy and the National Park Service. The park’s enabling legislation required an agreement be established between the Secretary of Energy and Secretary of the Interior within one year of the enactment of legislation to define each respective agency’s role in administering the facilities, land, or interest in land under the administrative jurisdiction of the Department of Energy to be included in the national park. To fulfill this mandate the agencies executed a memorandum of agreement on November 10, 2015, that outlined the agencies’ respective roles and responsibilities in co-managing the park.  

The National Park Service provides interpretation, education, and serves in an advisory role for historic preservation.  

The Department of Energy is responsible for management, operations, maintenance, access, and historic preservation activities of the historic Manhattan Project facilities, as all current sites included in the park are currently under its custody and control.

FAQs about Hanford, Washington


The Hanford Engineer Works produced plutonium at a roughly 600-square-mile (965-square-km) site along the Columbia River in Washington state. The Hanford Site was selected because of an abundant supply of cold Columbia River water needed to cool nuclear reactors, ample available hydroelectric power, mild climate, excellent transportation facilities, and distance from major population centers. Workers at the Hanford Site constructed and operated the world’s first nuclear production reactors that produced the plutonium used in the Trinity Test and in the atomic bomb dropped on Nagasaki, Japan, on August 9, 1945. 

The Hanford Visitor Center is located at 2000 Logston Boulevard in Richland, Washington.  Here you can watch our film “Hanford Made,” view exhibits, stamp your passport book, and pick up a junior ranger book. This is also the meeting location for the Department of Energy B Reactor Tours and Pre-war Historic Sites Tours. Learn more about the Manhattan Project at Hanford and planning a trip to visit the Hanford site.  

FAQs about Los Alamos, New Mexico


In Los Alamos, New Mexico, Manhattan Project administrators found an ideal location for the secret laboratory where they designed and built the world’s first atomic weapons. During the Manhattan Project, Los Alamos became the home to many of the top scientific minds of the day: J. Robert Oppenheimer, Norris Bradbury, Richard Feynman, Hans Bethe, and many more luminaries. These scientists, along with engineers and military officials, worked together to design, develop, and assemble atomic weapons, using enriched uranium from Oak Ridge and plutonium from Hanford. At 5:30 am mountain war time on July 16, 1945, an accumulation of scientific research culminated in the detonation of the world’s first atomic test device, codenamed the “Gadget” at the Alamogordo Gun Range in New Mexico, ushering the world into the atomic age. 

The Los Alamos Visitor Center is located at 475 20th Street in Los Alamos, New Mexico. At the visitor center you can speak with park rangers and park volunteers, stamp your passport book, view exhibits, get a junior ranger book, and learn more about Manhattan Project sites throughout the community. Learn more about the Manhattan Project at Los Alamos and planning a trip to visit the Los Alamos site.

FAQs about Oak Ridge, Tennessee


The rolling hills and narrow valleys of East Tennessee proved to be the ideal location for the top-secret atomic weapons program developed here beginning in 1942. Oak Ridge, Tennessee, was home to several massive Manhattan Project facilities employing thousands of workers during and after World War II and was the headquarters for the project after relocating from New York City. These facilities in Oak Ridge operated with one goal in mind: enriching uranium for use in the world’s first atomic bomb. Enriched uranium from Oak Ridge was used in the Little Boy atomic bomb dropped on Hiroshima, Japan, on August 6, 1945. 

The Oak Ridge Visitor Center is located within the Children’s Museum of Oak Ridge at 461 W. Outer Drive in Oak Ridge, Tennessee. Here you can speak with park rangers, watch a short film on the Manhattan Project, get a junior ranger book, stamp your passport book, and get more information about things to do and Manhattan Project sites throughout the city. Learn more about the Manhattan Project at Oak Ridge and planning a trip to visit the Oak Ridge site.

Last updated: June 23, 2023

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Contact Info

Mailing Address:

Manhattan Project National Historical Park
c/o NPS Intermountain Regional Office
P.O. Box 25287

Denver, CO 80225-0287


Hanford: 509.376.1647
Los Alamos: 505.661.6277
Oak Ridge: 865.482.1942

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