Zug Island is a heavily industrialized island within the city of River Rouge at the southern city limits of Detroit in the U.S. state of Michigan. It is located where the mouth of the River Rouge spills into the Detroit River. Zug Island is not a natural island in the river; it was formed when a shipping canal was dug along the southwestern side of the island, allowing ships to bypass several hundred yards of twisting waterway near the mouth of the natural course of the lowest portions of the River Rouge.