Hanford Site is a decommissioned nuclear production complex operated by the United States federal government on the Columbia River in Benton County in the U.S. state of Washington . The site has been known by many names , including Hanford Project , Hanford Works , Hanford Engineer Works and Hanford Nuclear Reservation . Established in 1943 as part of the Manhattan Project in Hanford , south-central Washington , the site was home to the B Reactor , the first full-scale plutonium production reactor in the world . Plutonium manufactured at the site was used in the first nuclear bomb , tested at the Trinity site , and in Fat Man , the bomb detonated over Nagasaki , Japan
Trinity site
Trinity (nuclear test)
Hanford Site