People of Hanford

A long line of men in work outfits.
Long lines at Hanford Construction Camp.


Approved as a top-secret Manhattan Project location by General Leslie Groves on January 16, 1943, Hanford was selected as the site for full-scale plutonium production. Led by the B Reactor, the flagship plutonium production reactor, Hanford saw a total of three reactors built for the project over 700 square miles of land seized by the Army Corps of Engineers. Thousands of people from diverse backgrounds worked at Hanford during the Manhattan Project; the nearby bedroom community of Richland saw its population increase to 15,000 residents as a result. In addition, approximately 15,000 segregated African American workers contributed to the war effort at Hanford. 
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    Last updated: June 16, 2023

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    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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