In the first two centuries of European exploration of North America, accounts of monsters, including ones given by Indigenous guides, were largely accepted by Europeans as reflecting actual creatures. Gradually, under the influence of a range of factors, this dynamic shifted over time. Continued exploration, the spread of Enlightenment ideas, and changing material circumstances led to a decline in the belief in monsters—or at least put the belief in them beyond respectability, thereby enlarging the cultural gulf between various Indigenous cultures and European explorers and settlers, or at least the social elite of that latter group. In Canada, as argued here, the “sasquatch” was a hybrid creation combining Indigenous and European traditions; the windigo was an Indigenous monster tradition; the “grisly bear” was predominately a monster of the European imagination. Perceptions of each in European exploration literature followed a similar trajectory of increasing skepticism. Each evolved from creatures that were depicted as innately hostile or dangerous into somewhat more benign pop culture images as they lost their potency once the frontier receded and North America urbanized. As the gap in perspectives on monsters widened in exploration and frontier literature over the course of the nineteenth century, new narratives emerged that were much more negative in their depictions of Indigenous peoples. Frequently, this negativity, when connected with monster legends, depicted Indigenous peoples as cowardly or superstitious. With the sasquatch, European stereotypes about Indigenous people had by the 1870s partially supplanted what had once been a sense of genuine mystery regarding this frontier legend. The exploitation of windigo stories to portray Indigenous peoples as cowardly and superstitious also arose mainly after the 1870s, as earlier generations of explorers and fur traders had exhibited more receptive attitudes. Meanwhile many voyageurs and lower status trappers retained beliefs on monsters closer to their Indigenous counterparts, and as a result were often lumped into the same category as sharing premodern, superstitious beliefs by their social elites. Finally, in the third example, the “grisly bear” became a bloodthirsty monster in the European settler imagination. It was the last mainstream European monster myth, before it too largely faded away in the face of skeptical inquiry. However, such skepticism, voiced normally from afar, frequently misunderstood and misconstrued the nature of these legends, and the truths they had contained. / Thesis / Doctor of Philosophy (PhD)