About Hanford

Black and white photo of rows upon rows of narrow buildings.
The Hanford Construction Camp housed 50,000 people at its peak.



At the roughly 600-square mile (965 sq km) Hanford Site, the Army Corps of Engineers and the DuPont Corporation built massive plutonium production facilities along the Columbia River in Washington State and forever transformed the site itself and the surrounding communities.  

The Hanford area’s contributions to the Manhattan Project and World War II started with the peoples living in and around the Priest Rapids Valley. In early 1943 the approximately 1,500 residents of White Bluffs, Hanford, the village of Richland, and nearby smaller communities were informed that the government had acquired their lands under the war powers authority. Landowners were given small settlements and 30-90 days to be off their land. The Army also barred area Tribes, who had used the area for traditional practices for time immemorial, from returning to the lands. They include the Confederated Tribes and Bands of the Yakama Nation, Confederated Tribes of the Umatilla Indian Reservation, and the Nez Perce Tribe, and the Wanapum People. 

During the Manhattan Project, Hanford’s mission was industrial-scale plutonium production by using nuclear reactors to irradiate uranium fuel rods, which were then dissolved in a series of chemical baths to allow tiny amounts of plutonium to be extracted from the irradiated uranium. Hanford then sent the plutonium to Los Alamos, New Mexico, where scientists designed, built, and tested the atomic weapons. Hanford’s mission required the construction of a vast and complex infrastructure spread across the site. Workers built three nuclear reactors along the Columbia River—each the size of a small city; three enormous chemical processing facilities; and a large fuel fabrication complex that produced more than a million pieces of uranium fuel for the reactors.  

From 1943-1945, the Army Corps of Engineers and its prime contractor, the DuPont Corporation, quickly recruited nearly 100,000 workers. At the peak of construction activity in late 1944, nearly 50,000 workers lived in the Hanford Construction Camp, which they built over the old Hanford townsite. Single men and women stayed in barracks or hutments. Families lived in many types of accommodations including trailer units and the homes of original residents. Of the workers, some 10% hired were women, mostly in clerical, foodservice, or domestic work positions. Approximately 14% were African American men hired mostly for low-skill construction jobs. Black women were hired in similar position to their White counterparts. The influx of thousands of African Americans to the rural Inland Northwest was unprecedented and permanently changed the demographics of the Tri-Cities area. Together, these workers constructed a vast plutonium production industrial complex, often while engineering designs were completed parallel.   

Operating the Hanford Site fell to DuPont employees brought to the area and housed in the transformed city of Richland, Washington. Formerly a small agricultural village, by 1944 Richland was transformed into a bedroom community of 12,000 atomic workers and their families. DuPont and the Army selected the Spokane architect Gustav Albin Pehrson to plan and oversee the development of an entire community consisting of hundreds of single- and multi-family houses known as the Alphabet Houses. Along with many prefabricated housing units these houses became the bedrock of a planned egalitarian community that foreshadowed the automobile-centric suburbs of postwar America. In contrast, African American workers were pushed to the east side of Pasco, literally on the “other side of the tracks,” an area lacking basic city services and comprised mostly of substandard housing.  

These Hanford operators produced weapons-grade plutonium in enough quantity to take the implosion method to create an atomic bomb from the conceptual stages into reality in just a few short years. The most powerful weapons of not just World War II, but of human history, atomic weapons have shaped geopolitics since their creation and divided historical time into a pre- and post-atomic world. 

Last updated: April 25, 2023

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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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