How did Minnesota get its shape?

Answer 1

Minnesota got its shape, because of the borders outlining the state. Minnesota's borders have a long and confusing history. 

NORTH: It took almost 142 years to determine, survey, and mark the northern border with Canada. A survey error, gave Minnesota (and the United States) the Northwest Angle, standing isolated on the Canadian side of the Lake of the Woods.

EAST: Basically, the eastern border followed the traditional fur trading water routes from the mouth of the Pigeon River, near present-day Grand Portage, and along Lake Superior. Various surveys selected points to connect the tip of Lake Superior to smaller rivers, until the border intersected the Mississippi River. The border followed the river to the Iowa border. The border's exact location, especially between Lake Superior and the Mississippi River was not determined until a survey in the 1920s.

SOUTH: The southern border is boring, compared to the other three borders. Minnesota and Iowa share a border on the south side of Minnesota that follows a latitude of 43.30 degrees (a simple staight line on the map).

WEST: The Western border was determined much the same as the eastern border, following traditional water routes until it did not make sense any longer. Then, surveyors followed a line directly south to the Iowa border.

Answer 2

See related links for a map of Minnesota and determine for yourself.