The Hanfor Site is a decommissioned nuclear production complex on the Columbia River in south-central Washington operated by the United States government. The site has been known by many names, including Hanford Works, Hanford Engineer Works, Hanford Nuclear Reservation, and the Hanford Project. Established in 1943 as part of the Manhattan Project, it 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.