A unique national resource, the Nevada National Security Site NNSS formerly known as the Nevada Test Site, is a massive outdoor laboratory and national experimental center that cannot be duplicated. Larger than the state of Rhode Island, approximately 1,375 square miles, the NNSS is one of the largest restricted access areas in the United States.
The remote site is surrounded by thousands of additional acres of land withdrawn from the public domain for use as a protected wildlife range and for a military gunnery range, creating an unpopulated land area comprising some 5,470 square miles.

Established as the Atomic Energy Commission's on-continent proving ground, the NNSS has seen more than four decades of nuclear weapons testing. Since the nuclear weapons testing moratorium in 1992 and under the direction of the U.S. Department of Energy (DOE), NNSS use has diversified into many other programs such as hazardous chemical spill testing, emergency response training, conventional weapons testing, and waste management and environmental technology studies.

Larger than many small countries, the NNSS offers an enormous amount of space, including more than a 1,000 miles of completely undisturbed land available for new projects. The vast site also offers security. The boundary and security areas are guarded, and the area is isolated from population centers.

On January 27, 1951, ABLE was the first atmospheric nuclear test detonated at the NNSS. When atmospheric testing ended in 1962, 100 atmospheric tests had been conducted. On August 5, 1963, all atmospheric testing was banned when the Limited Test Ban treaty was signed in Moscow, giving birth to the age of underground testing. The United States conducted 828 underground tests at the NNSS. The last underground test, DIVIDER, was conducted on September 23, 1992.

More information about atmospheric and underground testing as well as other unique historical information about the NNSS can be found at the Atomic Testing Museum .