The Manhattan Project

The Manhattan District was created as part of the U.S. Army's role in the Manhattan Project, under Colonel James C. Marshall. Initially headquartered in New York, the project later expanded to various sites, including one near Knoxville, Tennessee, for its proximity to resources like power and water. The project faced budget challenges, but high-priority status enabled it to secure the resources necessary for constructing production plants. The district eventually oversaw operations across multiple locations and was later led by Colonel Leslie Groves. NYC is where the North Atlantic Division of the Army Corps of Engineers was headquartered at the time and where the project got its name. Built in 1930, the building is now occupied by office, retail, and residential spaces.

The next decision was to select a not too densely populated remote location, away from potential German or Japanese bombs. After taking over the project, General Leslie Groves visited Tennessee with Colonel James Marshall and approved the site. In September 1942, the Corps of Engineers acquired 56,000 acres for $3.5 million, forcing 1,000 families to vacate, despite protests and legal challenges. The site became the Clinton Engineer Works (CEW), later known as Oak Ridge. It housed uranium production facilities and a residential community for 13,000, built by Skidmore, Owings & Merrill. By May 1945, Oak Ridge’s population peaked at 75,000, with 82,000 workers employed at CEW.

The idea of locating Project Y at Oak Ridge was considered, but a more remote location was chosen, following J. Robert Oppenheimer's suggestion. He recommended the area near Los Alamos, New Mexico, where he had a personal ranch. After a site visit on November 16th, 1942, the location was approved, and work began that December. Although it was initially meant to be a military lab, the University of California was contracted to operate the facility.

The preparations for the atomic bombings involved modifying B-29 bombers to carry the nuclear bombs and forming the 509th Composite Group under Colonel Paul W. Tibbets for the mission. Test drops of practice bombs were carried out, and bomb components were transported to Tinian Island. The bombings of Hiroshima and Nagasaki caused massive destruction and casualties. Following the bombings, Japan surrendered ending World War II. These events sparked ongoing debates about the necessity and ethics of using the bombs.

The project ended with the creation of the U.S. Atomic Energy Commission.