We Value Your Privacy

This site uses cookies to improve user experience. By continuing to browse, you accept the use of cookies and other technologies.


A Secret City in Tennessee Powered the Manhattan Project

Oak Ridge, established in 1942, was a key production site of uranium during World War II that fed the labs in Los Alamos.

A man sets up a machine at Oak Ridge National Laboratory
  • camera-icon
  • Photo Credit: Wikimedia Commons

It was one of the largest and most secretive operations ever carried out. The Manhattan Project employed over 130,000 people, cost the equivalent of over $20 billion in today’s dollars, and spanned more than 30 sites across the United States, England, and Canada, several of them so-called “secret cities” protected by fences and guards.

While we may associate the development of the first atomic weapons chiefly with “Project Y”, better known as the Los Alamos Laboratory in New Mexico, much of the work behind the development of the weapons—including the enrichment of the uranium needed to create the bombs themselves—was performed in the secret city of Oak Ridge, Tennessee.

Related: 10 Lost Civilizations That Vanished Without a Trace

Nestled in a 17-mile valley in the Great Smoky Mountains just west of Knoxville, the location of Oak Ridge was chosen for its isolation and its accessibility to power and water, thanks to the construction of the nearby Norris Dam. It was also chosen for its natural topography. The valley was separated by a series of ridges, which would prevent the project’s various industrial plants from exploding “like firecrackers on a string” in the event of a disaster.

The name Oak Ridge was chosen from suggestions put forth by the workers there, named for Black Oak Ridge, along which the secret city was built. Officials chose the name because they thought it sounded rural enough to keep “outside curiosity to a minimum”.

Holding off outside curiosity would be key, if officials wanted to keep the secrets of Oak Ridge. Between 1942, when the site was chosen, and 1945, when the first nuclear test occurred in the Jornada del Muerto desert in New Mexico, the population of Oak Ridge grew to more than 70,000 people, all of them tied in some way to the project. 

The secret city itself was surrounded by a fence with seven gates, which bristled with guard towers. The “City Behind the Fence”, as it came to be called, featured more than 300 miles of roads, ten schools, seven theaters, and a library with 9,400 books. At its peak, the city boasted sporting facilities, restaurants, church services for 17 denominations, and even a Fuller Brush salesman whose entire beat was Oak Ridge’s inhabitants.

Related: The Long, Strange History of the Maunsell Sea Forts 

Made up mostly of prefab homes formed from “cemesto”, a lightweight building material with a sugar cane fiber core surrounded by a mix of cement and asbestos, the entire city was designed by the architectural firm Skidmore, Owings and Merrill and was located at the eastern end of the valley.

A copy of Oak Ridge's commission by US Atomic Energy
  • camera-icon
  • Photo Credit: Bill McChesney / Flickr (CC)

West of the town itself were the three facilities used for enriching uranium and isolating the uranium isotope uranium-235, as well as the site that is now the Oak Ridge National Laboratory, at the time designated X-10 and used in the conversion of uranium to plutonium using a Graphite Reactor. The K-25 uranium-separating facility alone stretched across 44 acres of land and was the largest building in the world at the time.

The secrecy of the Oak Ridge project didn’t just extend from the inside out, either. The majority of the more than 70,000 people who lived and worked within the secret city didn’t have any idea what they were working on until Air Force planes dropped the first atomic bombs on the Japanese cities of Hiroshima and Nagasaki in August of 1945.

Related: Visiting Pripyat, Chernobyl's Frozen Ghost Town

Though the Manhattan Project itself and the construction of Oak Ridge was a minor miracle of quick engineering and bureaucracy, it didn’t exactly go off without a hitch. When Prentice Cooper, the governor of Tennessee at the time, was handed the official presidential proclamation from President Roosevelt designating Oak Ridge as a military district no longer under the state’s control, he tore it up without reading it, and initially refused to meet with the engineers sent to get the project underway.

The locals in the region weren’t always any happier with the project. In order to build the facilities and the “secret city” quickly, the Army Corps of Engineers claimed a lot of land, and didn’t always give residents much notice or compensation. 

The Peace Bell in Oak Ridge
  • camera-icon
  • The Oak Ridge International Friendship Bell, designed by Oak Ridge residents and cast in Japan.

    Photo Credit: Wikimedia Commons

Inhabitants of the county still remembered the land acquisitions that had occurred as part of the Tennessee Valley Authority’s construction of nearby Norris Dam just a few years before, and the ones associated with the construction of Oak Ridge were even more swift and brutal. Residents came home to find eviction notices on their doors, and were given six weeks—or even less—to get out.

The county wasn’t much better off, losing fully one-seventh of its land and nearly $400,000 in property tax revenue when the site switched over to military control. The rapid growth of the town also meant shortages for many of its residents and neighboring communities during wartime.

Nor was the whole thing entirely unforeseen, at least, not according to local tradition. John Hendrix was an eccentric resident of the area who died in 1915. Before his death, however, he claimed to see visions, including one that seems to have prophesied the coming of Oak Ridge and the Manhattan Project nearly three decades later.

“Bear Creek Valley someday will be filled with great buildings and factories, and they will help toward winning the greatest war that ever will be,” Hendrix was reportedly told by a voice from the sky, “as loud and as sharp as thunder.”

Related: History Book Deals Bring Fall Indoors

Neighbors and others later recounted Hendrix’s proclamations as continuing, “Big engines will dig big ditches, and thousands of people will be running to and fro. They will be building things, and there will be great noise and confusion and the earth will shake. I’ve seen it. It’s coming.”

Even after the first bombs fell in Hiroshima and Nagasaki, Oak Ridge remained shrouded under a veil of secrecy. Those who were displaced from their homes by the building of the site were still granted the right to bury their dead in the cemeteries near the area’s now-depopulated original churches. “But don’t think a spy or anybody could come in like a corpse in a coffin,” Oak Ridge residents reportedly told Life magazine after the war.

“They open up every coffin at the gates, they do, and they look at the corpse,” the anonymous Oak Ridger said, “and then they stick him with a needle to see if he’s sure enough dead.”

These continued security measures were seen as necessary, because the Oak Ridge facility actually produced more fissionable material—which locals simply called “the stuff”—after 1945 than it had during wartime.

Today, Oak Ridge remains a national leader in scientific and technological development, home to the Oak Ridge National Laboratory and the Y-12 National Security Complex, which leads efforts into decontamination and decommissioning of nuclear materials. While the fences may be mostly gone and the town hasn’t been under military control since the war ended, federal projects overseen by the Department of Energy are still the heart of the no-longer secret city’s economy and one of the largest single employers in the region.

Featured photo: Wikimedia Commons