Death Valley Days is by far the most successful syndicated television Western, the most successful television Western ever in the half-hour format, and one of the longest-running and most successful of all scripted syndicated series. The end of the series, coupled with the concurrent end of Gunsmoke, marked the end of the traditional Western era in American television, by the mid-1970s, although Western elements were still fairly common in modern series, pure Western series were a thing of the past. -- Wikipedia