Lake Erie
The shallowest and warmest of the Great Lakes
Lake Erie is the shallowest of the five Great Lakes, with an average depth of only about 62 feet and a maximum of around 210 feet (64 m). That shallowness makes it the warmest of the lakes, the quickest to freeze in winter, and the most biologically productive — its waters support the largest freshwater commercial fishery of the Great Lakes. It borders Michigan, Ohio, Pennsylvania, New York, and Ontario.
Because it is shallow and surrounded by farmland and cities, Erie is also the most vulnerable of the lakes to pollution. By the 1960s it was so degraded it was declared "dying," a crisis that helped spur modern environmental law, and though it recovered dramatically, it still suffers summer algal blooms. The lake drains east over Niagara Falls into Lake Ontario, the last step before the St. Lawrence.