Final answer:
The St. Lawrence Seaway borders the provinces of Quebec and Ontario in Canada, and the states of New York, Pennsylvania, Ohio, Michigan, and Minnesota in the United States.
Step-by-step explanation:
The St. Lawrence Seaway borders multiple states and provinces. On the Canadian side, the provinces of Quebec and Ontario are located along the seaway. Quebec, in particular, is the heart of the St. Lawrence River valley. On the United States side, the seaway borders the states of New York, Pennsylvania, Ohio, Michigan, and Minnesota.