The Lay of the Land

Michigan, Wisconsin and Minnesota form the northernmost tier of states in the Old Northwest. They all bound the upper Great Lakes (Lakes Superior, Michigan and Huron). Their abundant waters empty east into the St. Lawrence river and south into the Mississippi. (The waters of much of northwestern Minnesota follow a different course, emptying north into Hudson Bay.) The three states share a common northern border with Canada.

During the Ice Age, most of their area was covered for extended periods by glaciers, which left behind a vast plain covered with fine-textured soil and many lakes and rivers. Around Lake Superior the glaciers virtually stripped the rocks of sedimentary cover and thereby exposed an underlying geology going back more than three billion years. The three states share a continental climate relatively unaffected by coastal weather patterns. Temperatures range widely over the course of a year, tending to extremes often accompanied by the turbulence of hail, tornadoes and electrical storms. The area enjoys moderate precipitation, with the numbers declining in its western reaches.

When first found by the white man, most of the region was covered by virgin forests, of pine in the north and oak and hickory in the south. In western Minnesota, tall grass prairies extended like an ocean as far as the eye could see. The area surrounding Lake Superior was rich in metals, especially iron and copper. Southwestern Wisconsin had lead deposits that were important to the early development of that state.