This study aimed to characterize the forest communities of the national park of mont-Saint-Bruno (Québec, Canada). Specifically, it sought to identify sites with unique floristic compositions and to determine how this uniqueness was associated with various environmental variables. It also aimed to evaluate whether certain species were indicators of edge effects. This was done using data from plant surveys conducted in 133 plots in 2013. A total of 173 taxa were identified, including 21 exotic and 11 native at-risk species. Exotic species were generally low in abundance and frequency. Species richness and diversity were higher in plots located in depressions or at the bottom of slopes. Floristic communities in 8 plots were significantly different from the rest, due to the presence of wetland species. Edge indicator species were either shade-intolerant, tolerant to hydric stress, or ruderal. This study highlighted that the forest communities of the national park of mont-Saint-Bruno had few exotic species. It also showed that the vegetation of wetter sites differed from the otherwise homogenous flora in the park and that edges impacted plant community composition.