Operation Hardtack II
1958 - Nevada Test Site
Hardtack II included 37 tests, the largest test series so far, exceeding the 35 tests of the just completed Hardtack I. Hardtack I had focused primarily on high yield proof or developemental tests of complete thermonuclear weapons, which necessitated it be conducted in the distant Pacific (a total of 35.6 Mt being fired). In contrast, Hardtack II consisted exclusively of low yield tests, many of them attempted zero-yield one-point safety tests, which could be conducted in relative safety in Nevada (some were underground). Only 45.8 kt total was fired in Hardtack II, and of this only 18.5 kt was fired above ground.
The Los Alamos (LASL) shots had names taken from New Mexico counties. The Livermore (UCRL) shots had names of North American mountains, Roman gods and goddesses, and the fairies of A Mid-Summer Night's Dream.
Source: nuclearweaponarchive.org