If nothing else, "Law of the Rio Grande" demonstrates what you could buy for a couple of bucks and a box lunch back in 1931. There is certainly no lack of saloon extras or henchmen in this low budget affair from Syndicate Pictures, a forerunner of sorts of Monogram, niceties that would become prohibitive later in the decade. The cast is familiar and mostly made up of silent screen actors now down on their luck. It is not that Bob Custer and the others were necessarily terrible performers, but they were audibly unfamiliar with dialog and obviously received no help from a direction steeped in silent era film-making. The surviving print of "Law of the Rio Grande" is rather grim in places, a fact that adds to the overall ennui of the too-familiar story. Mark this down as an interesting piece of independent film-making in an era of transition.