What) Lake
Michigan is the only one of the Great Lakes wholly within the
borders of the United States. It has a surface area of 22,400
square miles, making it the largest lake entirely within one
country by surface area, and the fifth largest lake in the
world. It is 307 miles long by 118 miles wide with a shoreline
1,640 miles long. The lake's average depth is 279 feet, while
its greatest depth is 923 feet. It contains a volume of 1,180
cubic miles of water. The word "Michigan" originally referred
to the lake itself, and is believed to come from the Ojibwa
word mishigami meaning "great water". (1)
Lake Huron
is the second largest of the Great Lakes, with a surface area
of 23,000 square miles making it the third largest fresh water
lake on Earth. When measured at the Low Water Datum, the
lake contains a volume of 850 cubic miles and a shoreline
length (including islands) of 3,827 miles. The name of the
lake is derived from early French explorers who named it for
the Huron people inhabiting the region. Like the other Great
Lakes, it was formed by melting ice as the continental
glaciers retreated toward the end of the last ice age. Before
this, Lake Huron was a low-lying depression through which
flowed the now-buried Laurentian and Huronian Rivers; the lake
bed was criss-crossed by a large network of tributaries to
these ancient waterways, with many of the old channels still
evident on bathymetric maps.
Lake Huron is separated from Lake Michigan, which lies at the same level, by the narrow Straits of Mackinac, making them geologically and hydrologically the same body of water (sometimes called Lake Michigan-Huron and sometimes described as two 'lobes of the same lake'). Aggregated, Lake Huron-Michigan, at 45,300 square miles, "is technically the world's largest freshwater lake." (2)
Where) Not quite as easy to spot as Lake Superior
Why)
Looking at them on a map is one thing
but seeing them in person is another. After considering
this Buckys and one other, Pam and I
had a long discussion and decided for ourselves whether Lakes
Huron and Michigan were one lake or two. 
