When J. Robert Oppenheimer had proposed a central laboratory to the OSRD scientists in September 1942, they had endorsed it. After meeting with Oppenheimer, Arthur Compton (his superior in the OSRD hierarchy), and OSRD Director Vannevar Bush on October 19, Groves made the formal decision to establish the laboratory.
Groves initially thought of placing the laboratory at Oak Ridge--because most of the plants to make uranium-235 were planned for a site he had just acquired there--or in Chicago, where Compton's Metallurgical Laboratory was located.
But Groves subsequently believed that this project required a more remote site. It would need a climate that permitted year- round construction, safety from enemy attack, adequate transportation, and access to power, water, and fuel.
It would also have to provide adequate testing grounds and, for reasons of safety and security, should be in a sparsely populated area. Despite this last requirement, Groves also hoped that it would have sufficient buildings to house a small research staff.
After considering a site near Los Angeles, which he rejected on security grounds, and one near Reno, which he found unsuitable because of winter snows, Groves told Major John Dudley of the MED staff to survey the west for potential sites.
Dudley, borrowed from another district of the Corps of Engineers, was not supposed to know the purpose of the installation whose site he was seeking. However, after a short talk with Oppenheimer, Edwin McMillan, and the other scientists planning the new laboratory, Dudley "knew what they were doing quite thoroughly. I tried to turn them off, but within two minutes they would again be leaking information."
What Dudley most needed to know was how large the laboratory would be.
"Based on Oppenheimer's idea that six scientists, assisted by some engineers, technicians, and draftsmen, could do the job quite rapidly and effectively," and adding in support personnel, Dudley first estimated that 265 people would need to be accommodated.
After talking to Lawrence and Oppenheimer in Berkeley, he raised this number to 450, and, by the end of November, to 600. This size population determined the water supply, housing, and other resources that the new site would require.
Elaborating on his criteria, Groves specified that the site had to be at least 200 miles inland from the oceans or any international boundary and that sufficient housing had to be in place so that the six scientists could move in and start a think-tank immediately.
Groves also wanted a "natural bowl," ringed by hills, that could help secure the site and contain any accidental explosions .
"Toward the end of October 1942 I started out on my search," Dudley later recalled. "My plan was to visit the various Corps of Engineers offices in the southwest.
"I carried with me a letter from the chief of engineers that said 'give this man all the help he needs'....I traveled by air, rail and auto. Perhaps a thousand miles were covered on two-lane roads-one lane for the left wheels and one lane for the right wheels. When the going got tough, I switched to a jeep, and when it got even tougher, I rode a horse."
Dudley searched parts of California, Nevada, Utah, Arizona, and New Mexico in his travels. His first choice for the laboratory site was Oak City, Utah: "It was a delightful little oasis in south central Utah. The railroad was only 16 miles away over a nice, easy road. The airport was not too distant. The water supply was good. It was surrounded by hills, and beyond there was mostly desert. However, I noticed one thing: if we took over this area we would evict several dozen families and we would also take a large amount of farm acreage out of production."
Because of these impediments, Dudley recommended his second choice, the little town of Jemez Springs, New Mexico.
The hot springs there had attracted a resort hotel. There were a number of empty buildings but very few people who would have to be evicted. It was surrounded by mountains, with a small ridge that could separate the technical area from the residential area: "If the place blew up only the six scientists would be involved and not all the families." The access road was adequate to haul the scientific equipment that Oppenheimer, John Manley, and Ed McMillan wanted for the new laboratory.
Dudley's immediate superior, Marshall, approved the area for a site study, which was conducted by members of the Albuquerque Office of the Corps of Engineers. Oppenheimer and the OSRD scientists, however, also needed to approve the site. If they did, the new laboratory would be located on the western slopes of the Jemez Mountains of New Mexico.