A black and white photo of a blocky, industrial-looking building. A black and white photo of a blocky, industrial-looking building.

Left image
The B Reactor Building in 1944 under construction with the exterior nearly completed except for the tall ventilation stack.

Right image
The B Reactor today with its tall ventilation stack.

The Hanford Engineer Works produced plutonium for the Manhattan Project at a roughly 600-square-mile (1554-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. Explore all the places in the Tri-Cities Region related to the Manhattan Project through six common themes that weave the different places within the region together.

Choose a theme

  • Several people gathered in front of a large porch.


    Learn about the people who used to live and subsist off the land that became the Hanford Site.

  • Several people dancing indoors.

    Secret Cities & Communities

    Immerse yourself in the community and culture of the Tri-Cities during the Manhattan Project.

  •  A uniformed man walking toward a Jeep.

    Behind the Fence

    Peek behind the fence to explore plutonium production facilities and remnants of farm life.

  • An industrial facility with a water tower and smokestack.

    Breaking Scientific Boundaries

    Delve into the groundbreaking science of the Hanford Site and its connections to today.

  • Six men and women facing the camera.

    Untold Stories

    Discover the little-known stories of the Manhattan Project at Hanford.

  •  An aerial photo of a large factory on a riverbank.


    Follow the Manhattan Project's legacy at the Hanford Site from past to present.



Last updated: January 19, 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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