Pipeline projects in Canada often polarize citizens and governments from coast to coast. While the approval of such projects may seem simple from a constitutional standpoint, recent events show that legal realities and complexities truly add some grit in the works of pipeline projects even if the federal government is constitutionally responsible for the ultimate approval or refusal of projects because of their interprovincial nature. In fact, the passage of a pipeline involves a number of other considerations and fields of law, such as the environment, land use planning, risk management, and human rights, which are within the jurisdiction of federal or provincial legislatures, or both, and also increasingly the business of municipalities. While municipal powers continue, twenty-five years after important statutory reforms were launched, to be considerably limited by the provinces, courts have made it clear that municipal by-laws apply to federal pipelines, unless they have an excessive or serious detrimental effect on the construction or exploitation of such an undertaking, or if they contradict the operation or the purpose of federal legislation. It is in this multi-layered context that this article discusses the legal autonomy of Canadian municipalities in regard to the pipeline debate in Canada, exploring the content, the extent, and the limits of their powers.