About Oak Ridge

Black and white photo of man peering through equipment that are large circles.
Worker at K-25 Plant Oak Ridge Tennessee 1945



Oak Ridge, Tennessee was home to uranium enrichment facilities and the administrative headquarters of the Manhattan Project beginning in 1942, after moving project headquarters from New York, NY. Initially a rural region of rolling hills and narrow valleys in East Tennessee, this secret city was soon home to three massive uranium enrichment facilities: the Y-12 Electromagnetic Separation Plant; the K-25 Gaseous Diffusion Plant; and the S-50 Liquid Thermal Diffusion Plant. The X-10 Graphite Reactor, the world’s first plutonium-producing reactor, operated here as well until 1963. From 1943-1945, X-10 produced approximately 326 grams of plutonium which was shipped to Los Alamos.  

Prior to 1942 the area consisted of several small farming communities. When the US government purchased almost 100 square miles (260 square km) of land for the project in 1942, the roughly 3,000 original residents were forced off their land with minimal compensation, often given only a few weeks to relocate. 

Initially planned for 13,000 residents, the population of the secret city quickly expanded to more than 75,000 people during World War II, making Oak Ridge the most populous of the three primary Manhattan Project locations. Thousands of workers, including a sizeable segregated African American population, lived and worked here during the war, enriching uranium for use in Little Boy, the atomic bomb dropped on Hiroshima, Japan, on August 6, 1945. 

Oak Ridge remains a center of scientific research and nuclear production today. The Department of Energy employs thousands of people from across the country and the world to work at the Y-12 National Security Complex, Oak Ridge National Laboratory, and many other facilities. In addition, Oak Ridge is home to many museums and historic sites that tell the story of the secret city, from rural farming communities through the groundbreaking and controversial Manhattan Project to the present day. 

Last updated: April 14, 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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