Lake Michigan Overview


Lake Michigan is the only one of the five North American Great Lakes located entirely in the United States making it the largest body of fresh water in the United States.  Lake Michigan is the sixth largest freshwater lake in the world and the third largest of the North American Great Lakes by surface area. Lake Michigan and Lake Huron are joined by the Straits of Mackinac and are considered to be one lake hydrologically.  Lake Michigan is approximately 300 miles long and averages 75 miles across, covering 22,300 square miles which is approximately the size of Maryland, Delaware and Massachusetts combined. The Lake Michigan drainage basin includes the surrounding areas of Illinois, Indiana, Michigan and Wisconsin.   There are many rivers and streams flowing into Lake Michigan and the major tributaries are the Fox-Wolf, the Grand and the Kalamazoo.  In 1900, a channel and control structure was built reversing the flow of the Chicago and Calumet Rivers into the Mississippi becoming the largest out-of-basin diversion in the Great Lakes. 

Approximately 12 million people live along Lake Michigan with the majority concentrated within the Chicago and Milwaukee metropolitan areas. The northern part of the watershed is more sparsely populated with abundant forests and economically relies heavily on natural resources and tourism while the southern portion contains more industrial development and agricultural areas. The Lake Michigan shoreline feature the world’s largest freshwater dunes drawing millions of visitors annually to the beaches, state and national parks.  Lake Michigan is known for its excellent trout fishing including Chinook, Coho and Atlantic salmon as well as Rainbow, Brown and Lake Trout.


Surface Area 22,300 miles2 57,800 km2
Maximum Depth 925 ft 282 m
Watershed Area 45,600 miles2 118,000 km2
# of Fish Species 136*  
Water Retention/Replacement Time 99 years  


 Lake Michigan

aCoordinating Committee on Great Lakes Basic Hydraulic and Hydrologic Data, Coordinated Great Lakes Physical Data. May, 1992


Links to other resources:

Great Lakes Atlas - U.S. EPA