A mammoth and very rare set of thematic maps depicting historical changes in the channels of the Mississippi River, issued in 1941 by the Mississippi River Commission.

Background
Those living on the banks of the Mississippi have always been blessed by its fertile alluvial plain and ready water access to much of the American interior and the Gulf of Mexico. But, at least since the advent of European settlement, they have also been vexed by its propensity to silt up, change course, and flood to catastrophic effect. Efforts to tame the river date back at least to 1718, when the French at New Orleans began construction of a levee to protect the city. By the time of the Great Mississippi Flood of 1927 there were more than 1500 miles of levee along the river, which at best failed to prevent the disaster and at worst exacerbated it.

In 1879 Congress had established the Mississippi River Commission, charging it with developing and implementing plans to control the river’s channel, in order to improve navigation, facilitate commerce and prevent flooding. The Commission’s members were to include (and still include) both civilians and members of the Army Corps of Engineers and the U.S. Coast and Geodetic Survey. After the 1927 flood, The Flood Control Act of 1928 assigned the Commission vast new resources and responsibilities, including oversight of the entire tributary system of the river. To guide improvements in flood control the Act provided, among other things, for a survey of the river between Baton Rouge and Cairo, Illinois, where the Ohio merges with the Mississippi.

Map of Lower Mississippi River Stream Channels
That survey, conducted in 1930-32, provided the base for a remarkable 12-sheet map published in 1938 and documenting historic changes in the channel of the Mississippi at roughly half-century intervals beginning in 1765. Offered here is a 1941 update, also on 12 sheets, depicting the findings of the 1930-32 survey and another conducted in 1940-41.

Each sheet is a map in itself, including title, legend, imprint and neat line, but if placed end-to-end the full set of twelve would form a 50-foot strip map of the river from Cape Girardeau, Missouri 50 miles upstream from Cairo, to St. James Parish, some 40 miles downstream from Baton Rouge. The base maps, printed in black, are taken from the preliminary topographic quads of the 1930-32 survey and depict several miles on each bank of the river as it winds through Illinois, Kentucky, Missouri, Tennessee, Arkansas, Mississippi and Louisiana. Superimposed in colors are the course of the river in 1930-32 (yellow) and 1940-41 (orange)

With their considerable size and serpentine, intertwining bands of color, the maps are rather striking. Beyond their visual interest, the implications are shocking, at least for those accustomed to think of geography as fixed, or at most changing over a time scale of millennia. The maps make immediately evident how much the Mississippi’s course had changed in little more than a decade.

The 1938 and 1941 maps paved the way for an even more ambitious effort by the Mississippi River Commission, the 1944 Geological Investigation of the Alluvial Valley of the Lower Mississippi River. That work included a 15-sheet map, Ancient Courses: Mississippi River Meander Belt, which also used color to trace the river’s changing channel, but at no fewer than 30 successive time periods.

Given the huge population and the economic value of the agriculture and industry in the river’s floodplain, the Commission’s maps were a powerful call to action. Indeed, over the following decades billions were spent strengthening levees and constructing floodways to divert floodwaters, though all to little effect. Massive floods in 1973 and again in 1993 demonstrated that flood-control measures only increased the likelihood and severity of flooding.

In all, a spectacular set of maps of the Mississippi, both intrinsically interesting and significant for their influence on Federal attempts to control an ultimately uncontrollable force of nature.

Rarity and references
The 1938, 1941 and 1944 map sets are all reasonably well represented in American institutional map collections. However, they are vanishingly rare on the antiquarian market: I have never seen any of the three sets offered for sale, and neither RareBookHub nor Antique Map Price Record list any having appeared on the antiquarian market.

OCLC 21747511et al, giving 14 institutional holdings (June. 2022). Background from Hsieh Wen Shen and Eric Larsen, “Migration of the Mississippi River”, Berkeley: Department of Civil Engineering, University of California, July 1988; Alexis Madrigal, “What We’ve Done to the Mississippi River: An Explainer”, The Atlantic (May 19, 2011), accessed Feb. 2022 at theatlantic.com. See also Erin Kelly, “The Meandering Mississippi”, posted June 2, 2016 on the Library of Congress web site.