The Nuclear Information Project at the Federation of American Scientists estimated that the U.S. had about 3,700 warheads in its nuclear stockpile for delivery by aircraft and ballistic missiles, while Russia and China had 4,309 and 600, respectively.

Photograph of 74-kiloton nuclear bomb test Hood, conducted in 1957 at an altitude of 1,500 feet. Hood was the highest-yield atmospheric test to be conducted at the site, according to page 54 of the Nevada Test Site Guide published by the National Nuclear Security Administration (NNSA) Nevada Site Office in March of 2005. Image courtesy NNSA.