The Upper Mississippi River spans around 1,250 miles from Lake Itasca to Cairo.
Most of the Upper Mississippi goes through the center of the Driftless Area, around 15,000 square miles in Minnesota, Wisconsin, Iowa, and Illinois that has managed to stay free of glacial flows covering the past two million years.

It is defined by a multitude of limestone bluffs that have been molded all the way since the last ice age, due to water melting from glaciers.
The bottom of the river is composed of a thin layer of clay, silt, loam, and sand, which lay above a stratum of glacial outwash.

The Upper Mississippi River covers approximately half of the Mississippi River's length.
About 850 miles of the river is able to be navigated, from Minneapolis-St.
Paul to the Ohio River.
The river sustains a large variety of aquatic life, including 127 species of fish and 30 species of freshwater mussels.
The Upper Mississippi River spans around 1,250 miles from Lake Itasca to Cairo. Most of the Upper Mississippi goes through the center of the Driftless Area, around 15,000 square miles in Minnesota, Wisconsin, Iowa, and Illinois that has managed to stay free of glacial flows covering the past two million years. 
It is defined by a multitude of limestone bluffs that have been molded all the way since the last ice age, due to water melting from glaciers. The bottom of the river is composed of a thin layer of clay, silt, loam, and sand, which lay above a stratum of glacial outwash. 
The Upper Mississippi River covers approximately half of the Mississippi River's length. About 850 miles of the river is able to be navigated, from Minneapolis-St. Paul to the Ohio River. The river sustains a large variety of aquatic life, including 127 species of fish and 30 species of freshwater mussels.
Mississippi River System