It was World War 2. The United States was at war with Japan and Germany. We were fighting on two fronts and we needed to develop weapons to give us an advantage during the war.
Many of the German scientists escaped from Germany, bringing with them their pre-war research. The United States took advantage of this by having them work in secret developing weapons.
The main site for research and development was located in Los Alamos, New Mexico. The government too over the Los Alamos Ranch School with its huge campus with 54 buildings which included 27 were houses, dorms, and other living accommodations, a school, etc. This was perfect and it 16 miles away from the nearest town. By 1943, it was up and running fully.
The town was so secret, it did not appear on any map. Furthermore, there was only one post office box for all the mail coming to the site. Most people arrived in Santa Fe, before being taken to Los Alamos to work on creating and building the first plutonium atomic bomb. It took only 27 months for the "Manhattan Project" to produce meet its objective.
You probably wonder what this has to do with Oak Ridge, Tennessee. The government needed a place to produce the plutonium needed for the atomic bomb being built in New Mexico so as part of the "Manhattan Project", they built the town of Oak Ridge. The government used its right of eminent domain to clear people off of 60,000 acres of land, near the new TVA dam just outside of Norris, Tennessee. This dam produced the necessary electricity needed for the reactors used to make both Uranium and Plutonium.
In order to build the city quickly, three neighborhoods were built complete with schools, shopping, drug stores, beauty parlors, barbers and everything else a family might need, all within walking distance. Furthermore, the government arrange to have single family housing built and shipped into the "Secret City" one half at a time. At one point, houses were being built at the rate of one every 30 minutes.
Code named "Clinton Engineer Works", the facilities grew to employ over 75,000 people making it the 5th largest city in the state. In fact, for its first six years in existence, Oak Ridge was totally secret, just like Los Alamos. Things were so secure, the town did not appear on any maps, guards were posted at all entrances to the location, and all residents had to wear badges when they were outside their homes.
So New Mexico made the bomb and Tennessee produced the fuel. That is how the two are connected. Let me know what you think, I'd love to hear.