Water quality and suspended sediment monitoring and surveillance data collected from the connecting channels of the Great Lakes to determine baseline water quality status, long term trends and spatial distributions, the effectiveness of management actions, determine compliance with sediment quality objectives and identify emerging issues are included in this dataset. The Great Lakes are joined together by river systems known collectively as connecting channels, including the St. Marys River, the St. Clair River (and Lake St. Clair), the Detroit River, the Niagara River, and the St. Lawrence River. Uniquely, the connecting channels originate from the outflow of one or more large, oligotrophic lakes rather than the accumulation of a network of tributaries.