Glacial River Warren - Course

Course

While active this turbulent stream cut and eroded a bed up to 5 mi (8.0 km) wide and 250 ft (76 m) deep. This has left a valley which starts at Traverse Gap near Browns Valley, Minnesota, goes southeast to Mankato, then turns northeast to the Twin Cities. River Warren was joined by the comparatively small Mississippi at Fort Snelling, from which the valley continues northeast to present-day Saint Paul, where the massive River Warren Falls once graced the landscape. Over 1700 years this waterfall retreated upstream and undercut the Mississippi at the site of Fort Snelling. The falls then split. The Mississippi falls migrated upstream to form Saint Anthony Falls and create Minnehaha Falls in Minneapolis. The River Warren falls receded west in the Minnesota River valley until they reached an older buried river valley about 2 mi (3.2 km) west of the confluence, where the falls were extinguished.

From Saint Paul the great valley goes southeast to Prescott, Wisconsin, where it is joined by the St. Croix River, itself once the outlet of another proglacial lake, Glacial Lake Duluth which occupied the western part of Lake Superior. From its confluence with the St. Croix the valley continues southeast along the Minnesota-Wisconsin border. River Warren's effects include the creation of bluffs along the valleys of the Minnesota and Mississippi Rivers, and contributed to the formation of Lake Pepin.