Lake Iroquois

Lake Iroquois was a proglacial lake located where Lake Ontario is now located. As the Laurentide glaciation retreated it started to uncover the lake basin. But the glacier continued to fill what is now the valley of the St Lawrence River. Lake Iroquois was much deeper than Lake Ontario, coming to near the top of the Niagara Escarpment. The lake drained through the Mohawk River.