A previous study (Deutsch, 1991) demonstrated a striking difference in perception of the tritone paradox between subjects who had grown up in two different geographical regions. Specifically, a group of subjects who had grown up in California were compared with a group who had grown up in the South of England. When the Californian group tended to hear the pattern as ascending, the English group tended to hear it as descending, and vice versa. This raises the question of whether regional differences also exist within the United States in the way this pattern is perceived. The present study examined the percepts of subjects who had grown up in Mahoning and/or Trumbull counties in Ohio. Two groups were compared: those whose parents had also grown up in this area and those for whom this was not the case. A highly significant difference between these two groups of subjects was obtained, with those in the latter group producing a distribution of percepts similar to that found among Californians and those in the former group producing a different distribution. From this and other analyses of the data, it is concluded that regional differences in perception of the tritone paradox do indeed exist within the United States and that there is in addition an effect of familial background.