According to the ATF database, there are 4 registered FFLs in Milbank, South Dakota.
14719 S D HIGHWAY 15MILBANK, SD, 572520000
315 GAUSE AVENUEMILBANK, SD, 57252
1706 MORNINGSIDE DRIVEMILBANK, SD, 57252
15171 - 484 AVEMILBANK, SD, 572520000