The fort named for Louisiana GovernorMarquis de Vaudreuil-Cavagnial, was the furthest west on the Missouri at the time. Its first commandant was François Coulon de Villiers who came from an illustrious New France military family. Like many frontier forts it doubled as a trading post operated by Joseph Athanase Trottier dit Desruisseaux, who had a monopoly on trade on the Missouri from January 1, 1745 to May 20, 1750. Deruisseau chose the specific location of the fort because "the 'friendly Kansa were a dependable source of high grade furs' and the location was strategic". According to the Kansas Historical Society, the fort was:
Decline and abandonment
The fort felt into decline sometime after the French and Indian War. During this time, the area in which Fort de Cavagnial came under the power of Spain, although French soldiers remained at the site of the fort until 1764, when Pierre-Joseph Neyon de Villiers ordered that the troops stationed in the area to "throw down" the outpost and retreat to New Orleans. Evidently, the site was not completely razed, as in 1804, Meriwether Lewis and William Clark stumbled across the old site during their westward expedition, noting in their journal that " may be recognised by some remains of chimneys, and the general outline of the fortification, as well as by the fine spring which supplied it with water." In 1819, explorers on Stephen Harriman Long's Yellowstone expedition also made note of the ruin, describing them as "a few miles below Isle au Vache." By the mid-19th century, all traces of the fort were gone.
Location
The exact location of the fort is not known because of conflicting reports about its relationship to trade with the Kansa tribe. British reports placed it below the confluence of the Kansas River and Missouri in what is todayKansas City. However, most reports place it on the bluffs above the confluence of Salt Creek and the Missouri River just north of modern-day Fort Leavenworth. This was roughly in the same location as a major Kansa village. Lewis and Clark reported visiting this site on July 2, 1804: For decades, researchers, archaeologists, and scholars have "flown over in a helicopter, studied aerial photographs of it, driven around and over it, and walked over practically every square foot of it—and have found no definite trace of ." In 1987, the magazine Soldiers claimed that David L. Campbell, through the use of template mapping, had located foundations on a bluff that may have been the fort's remains. However, this claim has not been verified by archaeological evidence, and in 2004, the Kansas Historical Society claimed that the fort's exact location "remains as one of the active historical and archeological mysteries in Kansas."
