The association between environmental exposures and Parkinson’s disease continues to garner interest. In the late 1980s, Barbeau et al. reported in the Canadian Journal of Neurological Sciences a heterogeneous distribution of Parkinson’s disease cases across the province of Québec by hydrographic region. Here we report the findings of a validation study based on data obtained from the Québec medication insurance program–information which was unavailable to the previous group. Similar to Barbeau et al., our analysis showed a heterogeneous distribution of cases across the province with higher prevalence in the same region of interest, in addition to other areas.