Nuclear testing in Nevada began in the tense early years of the Cold War. In December 1950, President Harry S. Truman authorized the establishment of the Nevada Proving Ground—later renamed the Nevada Test Site—located about 65 miles northwest of Las Vegas. Chosen for its remote desert landscape and relative isolation, the site soon became the epicenter of America’s atomic weapons program. The first test, codenamed Able, took place on January 27, 1951, marking the start of an era that would profoundly shape both the region and the nation’s relationship with nuclear power.
Throughout the 1950s and early 1960s, the Nevada desert became a stage for more than 100 atmospheric nuclear explosions. Many of these were conducted above ground, producing massive mushroom clouds that could be seen from Las Vegas. Tourists and locals gathered on hotel rooftops to watch the tests, often unaware of the radioactive fallout drifting across communities in Nevada, Utah, and beyond. The spectacle, at first embraced as a symbol of American strength and technological prowess, soon gave way to growing fears about the long-term health and environmental consequences.
Mounting public concern over radiation exposure led to a turning point in 1963, when the United States, the Soviet Union, and the United Kingdom signed the Partial Test Ban Treaty, which prohibited nuclear tests in the atmosphere, underwater, and in space. From then until 1992, testing at the Nevada site continued underground, with more than 800 subterranean detonations carried out to refine and evaluate nuclear weapons designs. These underground tests reduced airborne contamination but caused other problems—seismic tremors, vented radioactive gases, and contamination of groundwater.
In 1992, after more than four decades of nearly continuous testing, the U.S. government declared a moratorium on nuclear explosions, effectively ending full-scale nuclear testing at the Nevada Test Site. The facility was later renamed the Nevada National Security Site (NNSS) and repurposed for subcritical tests, training, and research related to nuclear security and emergency response.
Today, the NNSS stands as both a symbol of Cold War ambition and a reminder of the human and environmental costs of the nuclear age. The legacy of testing still resonates in the stories of “downwinders”—residents who suffered from radiation-related illnesses—and in ongoing debates about transparency, responsibility, and the future of nuclear weapons policy in the United States.