Michigan has two separate land areas - the Upper Peninsula and the Lower Peninsula; and two major land regions: the Great Lakes Plain and the Superior Upland. The Upper Peninsula and the Lower Peninsula are connected by the five-mile (8km) long Mackinac Bridge, nicknamed “Big Mac”. The Lower Peninsula is part of the Great Lakes Plains. These plains stretch along the Great Lakes, from Michigan and Wisconsin to Ohio. The Lower Peninsula is fairly level, with some low rolling hills in the south. The lowest point in Michigan, along the shore of Lake Erie is found in the Lower Peninsula.
Flat, nearly featureless plains also occur in many parts of the state; these the floors of large glacial lakes that covered this area around 10,000 to 14,000 years ago. In the mid-19th century, most of these flatlaswds were malarial swamps that prevented settlement and farming. Over time the swamps were drained and the land used for farming. Large sand dunes rim the shores of Lake Michigan.
The western section of the Upper Peninsula belongs to the Superior Upland geographic region. This region extends runs along Lake Superior and into the Porcupine Mountains in northwestern Michigan. Mount Arvon, the highest point in Michigan, is found on the Upper Peninsula.
Michigan touches on four of the five Great Lakes, has a shoreline more than 3,250 miles long, and contains more than 11,000 lakes. Most of these lakes are glacial in origin, and range in size from less than an acre to the nearly 20,000 acres (8,100 hectares) of Houghton Lake in the north-central Lower Peninsula. Most of Michigan’s larger rivers are found in the southern part of the Lower Peninsula. Although several of the rivers, especially in the Upper Peninsula, have waterfalls, most of the state’s waterways are navigable or offer easy portaging. Compared with those in nearby states, most of Michigan’s rivers are short; distances from the headwaters to the mouths of the major rivers (which usually empty into one of the Great Lakes) are usually less than 150 miles (240 km).
The Straits of Mackinac separate Lake Michigan on the west from Lake Huron on the east. Between Lake Huron and Lake Erie, in the southeast, the Lower Peninsula is separated from the Canadian province of Ontario by Lake St. Clair and the St. Clair and Detroit rivers. The St. Mary’s River, which flows from Lake Superior to Lake Huron, forms the international boundary between the Upper Peninsula and Ontario.
About 500 islands dot the lakes and rivers of Michigan. Belle Isle, a public recreation centre, and Grosse Ile, largely residential, are well-known features of the Detroit River. Isle Royale, a virgin wilderness of almost 900 sq mi (2,300 sq km), is a national park in western Lake Superior, near Canada.
The Great Lakes cool the hot winds of summer and warm the cold winds of winter, giving Michigan a more moderate and somewhat moister climate than some other north-central states. Michigan has a temperate climate with well-defined seasons. The Upper Peninsula is cooler, but the temperature differences between Michigan’s far northern and far southern cities are not too great. In the far north, in Sault Saint Marie, January high temperature are usually in the low 20s F (about -6°C), while low temperatures hover near 5°F (-15°C); in July temperatures rise into the mid-70sF (about 24°C) and drop into the low 50s F (about 11°C) daily. In Detroit, in the southeast, January high temperatures usually reach the low 30s F (about 1°C), while lows fall to about 20°F (about -7°C); in July, high temperatures are typically in the mid-80s F (about 29°C) and lows are in the mid-60s F (about 18°C).
The coldest temperature ever recorded in the state is -51°F (-46°C), registered at Vanderbilt on 9 February 1934; the all-time high of 112°F (44°C) was recorded at Mio on 13 July 1936. Both sites are located in the interior of the lower peninsula, away from the influence of the Great Lakes. The wettest part of the state is in the southwest; Alpena, in the northeastern Lower Peninsula, is one of the driest sites in the United States east of the Mississippi River. Cloudy days are more common in Michigan than in most states. This is partly because of the condensation of water vapor from the Great Lakes.
