Los Alamos: Secret Cities & Communities

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Los Alamos was perhaps the most “secret” of the secret communities associated with the Manhattan Project. No one ever mentioned Los Alamos by name. It was simply known as "Site Y" or "The Hill." The entire town only had one mailing addressPO Box 1663 in Sante Fe. Everyone, including children, had to wear a government-issued identification badge. 

Yet, Los Alamos had schools, a hospital, a general store, and all the amenities and services of a not-so-secret community. The people there interacted with local communities including the San Ildefonso Pueblo. So, what was it like to live life under the cloak of secrecy? Visit the sites below to find out. 

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    Last updated: December 7, 2021

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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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