For the Great Lakes Region, what is the corresponding designator?

The correct designator for the Great Lakes Region is GL. This designator is widely recognized and used in different contexts such as environmental management, political divisions, and geographical studies to specifically refer to this region. The term "Great Lakes" encompasses the five lakes—Superior, Michigan, Huron, Erie, and Ontario—and their surrounding areas, which play a significant role in trade, transport, and ecology in North America.

This specificity helps in data categorization and regional planning, making GL the most appropriate choice when referring to the Great Lakes as a distinct geographical and cultural area. The other designators provided do not correspond specifically to the Great Lakes Region, which is why they are not suitable alternatives.