Proper scoping is essential for any environmental assessment (EA) process. This is particularly true with respect to resource development in the intercultural setting of First Nation homelands of northern Canada. Improper scoping leads to EAs that are flawed for a number of reasons. For example, potentially impacted stakeholders are excluded from the process; thus, the proper collection of baseline information is not possible resulting in inaccurate predictions of impacts and mitigation strategies. We examined whether the approved EA for the Victor Diamond Mine in northern Ontario was properly scoped using criteria identified by the Government of Canada, in their project-specific guidelines developed for the assessment. Our results from the published literature, which included oral history, clearly indicate that the Victor Diamond Mine EA scoping process was based on two erroneous assumptions: that the registered trapline system was the accepted system of land use/occupation in northern Ontario, and that land use/occupancy was based on the treaty-imposed reserve system (not the family-based traditional lands system). Implications for resource development involving indigenous people are discussed.