JOHN L. ALLEN
In 1821 the city-village of St. Louis had probably the most strategic location in North America. A former colonial outpost of both France and Spain, St. Louis had become an American possession with the purchase of the Louisiana Territory in 1803 and continued to serve, as it had since its founding, as the gateway to both the Northwest, containing the drainage basins of the Missouri and the Columbia Rivers, and the Southwest, the area south of the Missouri's drainage basin. In the Northwest, the region east of the Rocky Mountains was indisputably American territory by virtue of the Purchase. West of the continental divide, both British and American interests laid claim to "Oregon Country." In the Southwest, that part lying east of the Rocky Mountains was also within the Territory of Louisiana and was therefore American territory. But Mexico claimed much of the Southwest, particularly south of the Mississippi's western tributaries and west of the Rockies, as part of what had been the "Interior Provinces" of New Spain before Mexican independence. St. Louis, therefore, occupied a geographical location of enormous political and economic significance.
A key aspect of the geostrategic position of St. Louis was its traditional role as the heart of the fur trade of western North America below the forty- ninth parallel.1 Here, in the waterfront taverns and warehouses nestled under the bluffs of the Mississippi's western shore, fur trade families such as the Chouteaus conducted the business that brought the wealth of "brown gold" to this gateway to the Northwest and the Southwest. Since the mid- 1700s, these families had dominated the fur traffic of the Missouri River between St. Louis and the Indian nations of the Missouri's upper reaches-- the Sioux and Mandan and Arikara and Hidatsa Indians.2 The scions of these St. Louis families had rarely engaged in exploration themselves; but they had sent their employees into the region of the Missouri's Great Bend