On July 17, 1955, Arco, Idaho became the first U.S. town to be powered by nuclear energy. The demonstration lasted for one hour in the 1,350-person community. The National Reactor Testing Station, now called the Idaho National Engineering Laboratory, supplied the power from its Borax-III reactor. It was part of the Atomic Energy Commission's (AEC) Five-Year Reactor Development Program in the mid-1950's. The AEC tested five types of experimental reactors. The Borax-III was an early prototype of a boiling water reactor, a type of reactor which still produces electricity for utilities today.
This information is taken from this web site.
http://www.radiochemistry.org/history/nuclear_timeline/50s.html
I took this photograph when driving through Arco on the way to the Craters of the Moon, a fascinating place, 26 miles from Arco, Idaho
This is a cone mountain, fine pieces of lava piled quite high in Craters of the Moon National Monument. I climbed part way, rather slick and steep.