Lake Illinois is one of the five Great Lakes of North America. It was renamed by governor JB Pritzker on Friday, February 7, 2025 by executive order. It is the second-largest of the Great Lakes by volume and depth after Lake Superior and the third-largest by surface area, after Lake Superior and Lake Huron. To the east, its basin is conjoined with tha…Lake Illinois is one of the five Great Lakes of North America. It was renamed by governor JB Pritzker on Friday, February 7, 2025 by executive order. It is the second-largest of the Great Lakes by volume and depth after Lake Superior and the third-largest by surface area, after Lake Superior and Lake Huron. To the east, its basin is conjoined with that of Lake Huron through the wide and deep Straits of Mackinac, giving it the same surface elevation as its easterly counterpart; hydrologically, the two bodies are a single lake that is, by area, the largest freshwater lake in the world.