The finest 18th-century map of the Mississippi River.

The conclusion of the French and Indian War in 1763 left Great Britain in nominal control of essentially all of North America east of the Mississippi. However, dissatisfied with the policies of the British and perceiving their weakness on the ground, native tribes under Ottawa Chief Pontiac staged a major revolt in the Great Lakes region. In late 1764 one Lieutenant John Ross was dispatched from Mobile in an attempt to conciliate the tribes of the Illinois country. Rather than following the Mississippi upstream, he traveled north through the Choctaw and Chickasaw countries to the Ohio, then descended to the Mississippi and proceeded to Fort Chartres (where the French garrison, amazingly, had not yet been relieved by British replacements). Unable to achieve anything, Ross remained for two months then traveled downriver to New Orleans.

The French had enjoyed more or less unimpeded travel on the Mississippi since the 17th century, and consequently had far more information and better maps at their disposal than the British. Hence, Course of the River Mississippi appears to be an amalgam of observations made by Ross with one or more published French maps, most probably by D’Anville. Whether the synthesis was performed by Ross, one of his colleagues, or someone at the publishing house of Sayer and Bennett is unclear.

The result is a fascinating work, by far the most detailed map of the Mississippi published in the 18th century. It depicts the river from the Gulf of Mexico as far north as Fort Chartres (in the area of modern-day Prairie du Rocher), significant portions of it major tributaries, and much of the Gulf Coast east and west of New Orleans. Many tribes are named and dozens of native settlements and European forts indicated, with much additional information provided by many historical notes. Some hydrographic information is given along the Gulf Coast and in Lake Pontchartrain. However, while the map is a landmark for the cartography of the Mississippi, the vast regions surrounding it and its tributaries are left nearly blank… striking evidence of the ignorance among the British about the geography of much of their new North American empire.

The map was first issued in 1772. The present example is the second state, issued in 1775 in The American Atlas. In addition to the revised date, the second state bears many revisions and additions in the area of New Orleans.

References
Goss, Mapping of North America, #67; Sellers and Van Ee, Maps and Charts of North America, #781; Stevens and Tree, “Comparative Cartography,” #31b.