Human activities are breaking down barriers to interpopulation hybridization with results that range from populations that resist introgression to populations at serious risk of genetic extinction, particularly between wild and hatchery fish because of the routine stocking of lakes and streams containing wild populations. We investigated whether specific human actions and (or) habitat characteristics were associated with the extent of hybridization between hatchery and wild brook trout (Salvelinus fontinalis) occupying lakes in Algonquin Park, Ontario, Canada. Hatchery and wild trout tended to hybridize more in lakes (i) supporting smaller populations (i.e., having lower pH and situated at higher elevations), (ii) stocked earlier in the season, and (iii) with greater exposure to other human activities (fishing). Our results highlight how particular human activities may interact with specific habitat conditions to elicit hybridization in wild populations. Hence, the use of readily available habitat and land use data may provide an economical means of anticipating hybridization or identifying indigenous populations with minimal introgression.