Fort Beauharnois, erected in 1727, is considered to be the last French fort in operation along the Mississippi. (It is presumed that the fort was constructed on a low point of land in Lake Pepin, now known as Point au Sable (Sand Point). Although a number of archaeological investigations have been conducted, no evidence has been discovered that Fort Beauharnois was actually located at this site.) Since the 17th century, the French had been exploring what is now Minnesota and developing a system of forts along the Mississippi River from which they explored the countryside and sought the headwaters of the Mississippi River. Rene Boucher and an expedition from Montreal arrived on the shores of Lake Pepin in June 1727, established a trading post with the Dakota, and erected a fort which they named for the Marquis de Beauharnois, Governor General of New France (Canada). The fort was to be the outpost from which the French would establish a fur trade with the Dakota and begin their search for a route to the "Western Sea." Holmquist writes that:
"The notion that the fort could be used to further explorations toward the Western Sea was undoubtedly a powerful motivating force in its establishment. The pursuit of a route across North America to the Pacific Ocean was one of the dominant objectives of the period. Many men searched for it, all of them unaware of the vast width of the continent that balked their success" (Holmquist 1972:91).
Fowell describes the fort and its structures in A History of Minnesota:
"A substantial fort was erected, consisting of a stockade one hundred feet square of tree trunks set on end twelve feet out of ground, 'with two good bastions,' each of which gave a flank fire on two sides of the work. Within were three log buildings, all sixteen feet wide, one thirty feet long, another thirty-eight, the third twenty-five. Upon the completion of the work the garrison celebrated in November the birthday of Beauharnois, the governor of Canada, whose name was give to the post" (Folwell 1921:46).
Two Jesuit missionaries accompanied the expedition and established what is thought to be the first Christian church in Minnesota -- the Mission of St. Michael the Archangel, a small chapel erected in 1727 within the stockade. Cabins, a blacksmith shop, and warehouse were constructed outside of the stockade. The fort and mission were abandoned in 1736 following the signing of the treaty with Britain in which Great Britain gained control of North America.