According to the ATF database, there are 5 registered FFLs in Hermosa, South Dakota.
14366 HASSELSTROM PLHERMOSA, SD, 57744
275 MANNINGHERMOSA, SD, 577440000
14139 SD HIGHWAY 36HERMOSA, SD, 57744
24647 SADDLE RIDGE RDHERMOSA, SD, 57744
13885 THISTLE RIDGE RDHERMOSA, SD, 57744