I.

Introduction

Great Lakes, group of five large lakes, central North America. From east to west, they are Lakes Ontario, Erie, Huron, Michigan, and Superior. Lake Michigan lies entirely within the United States, but the other lakes straddle the border between the United States and Canada. All are jointly controlled by the United States and Canada under the Boundary Waters Treaty of 1909. The total surface area of the Great Lakes is 244,108 sq km (94,251 sq mi), making them collectively the largest body of fresh water in the world. Together they hold about 20 per cent of the world’s fresh surface water; approximately two thirds of their surface area is within the boundaries of the United States. The lakes drain a basin of about 751,100 sq km (290,000 sq mi), an area slightly less than the size of Turkey. They serve as the focus for the industrial heartland of North America, and also provide an important recreational resource with about 17,000 km (about 10,625 mi) of shoreline. For further details see the separate article on each lake.