St. Anthony Falls is located northeast of downtown Minneapolis and was the only natural waterfall on the Upper Mississippi River. The falls were replaced by a concrete overflow spillway after part of the falls collapsed in 1869. Due to a series of dams and locks being constructed in the 1950s and 1960s to extend navigation the falls are known today as Lower Saint Anthony Falls and refers to a downstream lock, which is referred to as Upper Saint Anthony Falls.
The falls were named after the Catholic saint Anthony of Padua, the falls were the birthplace of former city St. Anthony and Minneapolis when the two cities joined in 1872. The cities joined to utilize the economic power of milling operations.
Geologists believe that the falls appeared around 10,000 years ago downstream at the confluence of the Glacial River Warren - Ft. Snelling. They believe that the falls were around 180 feet high and have moved upstream over the centuries, breaking off chunks of limestone cap as it receded. The geological formation of the area was a thin layer of Platteville Formation, carbonate rock, which overlays the St. Peter Sandstone surface. The churning waters at the bottom of the falls have eaten away at the sandstone resulting in large blocks of Platteville formation falling off.
The falls became a source of power for several industries including sawmills, textile mills and flour mills. Due to Millers creating a consortium on the Minneapolis side and diverting water into a waterwheel equipped vertical shaft then through horizontal tunnels, caused the falls upriver erosion to accelerate and almost lost the edge of their limestone cap.
The upper limit of commercial navigation was at St. Anthony Falls until the dams and series of locks were built between 1948 and 1963. This made commercial navigation possible along the length of the Mississippi River. The falls are now known as upper St. Anthony Fall's dam, which is a horseshoe-shaped hydro-electric dam, which is 93 feet high and was completed in 1963 and the lower St. Anthony Falls dam, which is a gravity-type hydro-electric dam. that is 60 feet high and was complete in 1956.
The current around the spillway/falls can be quite swift and dangerous. A small boat that could drift to close could have catastrophic consequences such as in 1991 when two people were killed and two other rescued by helicopter when their boat fell over one part of the dam.
The falls are the only major waterfall on the Mississippi River, but the city of Minneapolis used the water resource to create power rather then as a form of transportation like most other cities developed around water. The falls were instrumental in developing Minneapolis through providing natural beauty, provided power to the lumber and flour industries and electrical power for industrial and residential use.
The falls and the area surrounding them were added on the National Register of Historic Places in 1971 as the Saint Anthony Falls Historic District and include 8th Avenue Northeast downstream to 6th Avenue Southeast and two city blocks on both shorelines.
