Driftless Area

43°30′N 91°00′W / 43.5°N 91°W / 43.5; -91The Driftless Area, also known as Bluff Country and the Paleozoic Plateau, is a topographical and cultural region in the Midwestern United States^[1] that comprises southwestern Wisconsin, southeastern Minnesota, northeastern Iowa, and the extreme northwestern corner of Illinois. The Driftless Area is a USDA Level III Ecoregion: Ecoregion 52. The Driftless Area takes up a large portion of the Upper Midwest forest–savanna transition. The Blufflands refers to the eastern section of the Driftless area in Minnesota, due to the steep bluffs and cliffs around the river valleys. The western half is known as the Rochester Plateau, which is flatter than the Blufflands.^[2] The Coulee Region refers to the southwestern part of the Driftless Area in Wisconsin. It is named for its numerous ravines.

Never covered by ice during the last ice age, the area lacks the characteristic glacial deposits known as drift. Its landscape is characterized by steep hills, forested ridges, deeply carved river valleys, and karst geology with spring-fed waterfalls and cold-water trout streams. Ecologically, the Driftless Area's flora and fauna are more closely related to those of the Great Lakes region and New England than those of the broader Midwest and central Plains regions. The steep riverine landscape of both the Driftless Area proper and the surrounding Driftless-like region are the result of early glacial advances that forced preglacial rivers that flowed into the Great Lakes southward, causing them to carve a gorge across bedrock cuestas,^[1] thereby forming the modern incised upper Mississippi River valley.^[3][4] The region has elevations ranging from 603 to 1,719 feet (184 to 524 m) at Blue Mound State Park, and together with the Driftless-like region, covers 24,000 square miles (62,200 km²).^[5]