Fort Orleans, established by Bourgmont about 1723, was the first military post ever built on the Missouri river, though its exact location is largely a matter of speculation. Du Pratz says: "There was a French post for some time on an island a few leagues in length over against the Missouris. The French settled in this fort at the east point [of the island] and called it Fort Orleans." This statement appears to have been accepted without question by some later writers, notably Chittenden, in his "American Fur Trade," and Prentis, in his "History of Kansas." Chittenden says: "The actual location was about 5 miles below the mouth of Grand river, opposite the old village of the Missouris," and Prentis locates the island "near the mouth of the Osage."

Thwaites' edition of the Lewis and Clark journals says: "The exact site of Fort Orleans is not definitely known, and there are diverse opinions regarding it." Hon. Walter B. Douglas, of St. Louis, thinks that the fort was "on the north bank of the Missouri, above the mouth of Wakenda creek, in what is now Carroll county, Mo., and 15 or 20 miles above the town of Brunswick." This would place the fort nearly opposite Malta Bend, where Coues locates it. But, wherever it may have been, authorities generally agree that it was erected for a trading post, and to guard against a Spanish invasion. Chittenden says: "There is a tradition that when Bourgmont left the fort a year or two later to go down to New Orleans, the Indians attacked it and massacred every inmate." (See Bourgmont's Expedition.)