Barn Bluff is a bluff along the Mississippi River in Red Wing, Minnesota, United States. The bluff is associated with Dakota legend from hundreds of years ago. During the 19th century, the bluff functioned as a visual reference for explorers and travelers. The bluff overlooks the downtown area and towers about 400ft above the Mississippi River with an extensive view of Lake Pepin to the south. It is one of hundreds of bluffs in the Driftless Area, which covers parts of Wisconsin, Iowa, and Illinois, in addition to the southeastern toe of Minnesota.GeologyMost of the bluff is displaced approximately 40m upwards relative to the adjoining bedrock along the Red Wing Fault, which transects the bluff near its south face. It is composed of early Paleozoic rocks, including Ordovician dolomite and sandstone atop Cambrian shale, siltstone and greensand at its base, deposited by early Paleozoic seas. The aggregates left by glacial drift and wind-deposited loess form a 20m cap deposited some 450 million years after the bedrock beneath. Barn Bluff was cut off from nearby uplands by an earlier course of the ancestral Mississippi along which US Highway 61 now runs, and it was an island during the massive outflow of Glacial River Warren which carved much of the present Upper Mississippi Valley.
