The Secret City in Tennessee Turns 80 This Year - Rich History is Preserved and Knowlege Shared

John M. Dabbs

Oak Ridge

Why Oak Ridge Was Chosen for the Manhattan Project

Oak Ridge, the so-called “Secret City” was at the epicenter of the Manhattan Project, the American-led effort to build an atomic bomb.

Since the fateful events of August 1945, many people have wondered why Oak Ridge was chosen for the Manhattan Project.

General Groves

According to City Behind A Fence, a history of Oak Ridge during WWII, the decision to build a nuclear development site in East Tennessee was made personally by General Leslie Groves on September 19, 1942. Groves had only been appointed the commander of the Manhattan Project two days prior.

A number of locations for the nuclear site were considered over the summer. The other sites were too small or vulnerable to enemy attack. Groves found the site scouted in East Tennessee had nearly ideal conditions for the military’s plans.

  1. Remote Location
    Groves wanted to ensure that the Manhattan Project kept a low profile, and Oak Ridge’s rural location definitely fit the bill.
  2. Perfect Population Size
    East Tennessee had just the right amount of people for the Manhattan Project’s purposes.
  3. Land, Water, and Electricity
    In September 1942, the Manhattan Project planned on building four different types of production plants at one site. The original plan to construct all four plants in the same vicinity contributed to East Tennessee’s appeal. The electromagnetic, gaseous diffusion, and thermal diffusion plants all required significant amounts of electricity, which could be found at the Tennessee Valley Authority hydroelectric plants at Norris Dam. East Tennessee also offered good quality water and ample land for the project. As an added bonus, the land was cheap: only $48 per acre, on average.

The Secret City is Born

Under orders from General Groves, the U.S. Army Corps of Engineers purchased 59,000 acres of land along the Clinch River.

Throughout the war, Oak Ridge was protected by guarded gates, and workers at the plants were sworn to secrecy. Few people in town were aware that the military was pursuing an atomic bomb onsite; they only knew information relevant to their specific job duties. It was not until the attacks on Hiroshima and Nagasaki in 1945 that the true purpose of the Secret City became clear to the masses.

Oak Ridge, Tennessee, is not just home to the Manhattan Project that helped end World War II, it is the present home of Oak Ridge National Laboratory and the Y-12 National Security Complex.
Oak Ridge, TennesseeUS DOE/Flickr

Manhattan Project

Oak Ridge was instrumental in the United States' win over Japan during WWII because of the development of the atomic bomb. Known as the “Secret City”, Oak Ridge was not on any maps and 100,000 workers were brought to the city to work on a Top Secret war project, known as the Manhattan Project.

The Manhattan Project brought the minds of physicists, chemists, mathematicians, engineers, and the military to expand the limits of technological achievements never before imagined. The Manhattan Project National Park consists of 3 cities; Oak Ridge, Tennessee, Los Alamos, New Mexico, and Hanford, Washington. The National Park is designed to educate the public and interpret what some have called “the single most significant event of the 20th century,” the development of the atomic bomb and the introduction of the Nuclear Age.

Newly opened in 2015, this historic park features sites, facilities, equipment, and artifacts associated with the unprecedented top-secret government program. The project enabled the U.S. to develop atomic weapons that brought an end to World War II. The legacy of the Manhattan Project is seen in many areas such as space travel, nuclear medicine, and energy production to name a few.  The Manhattan Project National Historical Park tells the stories of people, events, science, and engineering that changed the world.


As a result of the ongoing research beyond the Manhattan Project, the U.S. Department of Energy (DOE) provides expertise around the country and around the world. The Radiation Emergency Assistance Center/Training Site (REAC/TS) is a world-renowned, U.S. Department of Energy asset and a leader in the emergency medical response to radiological/nuclear incidents. REAC/TS provides emergency response and subject matter expertise on the medical management of radiation incidents for the National Nuclear Security Administration’s (NNSA) Office of Counterterrorism and Counterproliferation. REAC/TS is located at the Oak Ridge Institute for Science and Education in Tennessee and is operated for DOE by ORAU (Oak Ridge Associated Universities).

24/7 response capability for advice and consultation on radiological emergencies

REAC/TS maintains a national and international response capability and provides continuing medical education and outreach exercises. REAC/TS courses annually reach thousands of healthcare professionals, emergency responders, and health physicists worldwide. Topics address the medical management of radiological/nuclear incidents, as well as decontamination techniques through instructional and hands-on education.

REAC/TS also operates a unique laboratory that helps DOE close a critical gap in our nation's ability to respond to a radiological or nuclear incident. The REAC/TS Cytogenetic Biodosimetry Laboratory utilizes the “gold standard” dicentric chromosome assay, a proven technique that can be used to help calculate the absorbed radiation dose in exposed individuals.

REAC/TS recently helped the medical facilities around the Kennedy Space Center prepare with mitigation training, for a recent launch of a nuclear-powered rover that NASA launched to Mars.

American Museum of Science and Energy
John Dabbs/Photographer

Among the other sites and off-limits areas within Oak Ridge in the present day, you can visit the Smithsonian Institution's American Museum of Science and Energy. The museum provides an overview of how the city of Oak Ridge was built in secret during World War II and the developments of the Manhattan Project.
John Dabbs/Photographer

That isn't all. The museum also covers some of the other innovations which have taken place at Oak Ridge and the science and technology expansion that has taken place because of the work done in the city. The museum has many hands-on exhibits and is perfect for kids of all ages. The entry fee is very affordable and can be gone through in a couple of hours.
3-D printed Jeep, printed on printer developed at Oak Ridge National LaboratoryJohn Dabbs/Photographer


Established in 1943 as part of the Manhattan Project, Oak Ridge National Laboratory is building on a legacy of discovery and innovation to continually address the most urgent R&D needs of the U.S.

  • The Proton Power Upgrade and Second Target Station will open new frontiers in materials research at the Spallation Neutron Source
  • Frontier, ORNL’s exascale computer, will deliver world-leading performance in 2022
  • ORNL assets are being focused on national artificial intelligence and quantum initiatives
  • New materials, software, and systems for advanced manufacturing developed at ORNL are transforming nuclear energy technology
  • Cybersecurity technologies developed by ORNL are improving the resilience of the nation’s electric grid and other critical infrastructure
  • Researchers are advancing biotechnology to convert plastics into valuable chemicals.

For more information on ORNL or their supercomputers, visit their website at

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An outdoor enthusiast with a passion for travel and adventure. John is a professional consultant and photojournalist.

Bristol, TN

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