Civil War "West": Rivers and Rails

From The Civil War at Sea, by Craig L. Symonds (Praeger, 2009), Kindle Locs. 1304-1325:

It is important to acknowledge that during Civil War, "the West" referred not to places like Arizona and New Mexico, or even Texas and Arkansas, which constituted the "trans-Mississippi West," but instead to the expanse of territory between the Appalachian Mountains and the Mississippi River. The Ohio River marked its northern boundary, and the Gulf of Mexico its southern, and it encompassed all or part of six states: Louisiana, Mississippi, Alabama, Tennessee, Kentucky, and Georgia. It may seem odd to think of Georgia as part of the West since it borders the Atlantic Ocean, but strategically much of Georgia—especially Atlanta—was more closely tied to the West than the East. This vast western area got less public attention than the epic battles in Virginia both at the time and subsequently, and until recently Civil War literature tended to treat it as a secondary theater, though a good argument can be made that this expansive region was the decisive theater of the war.

Moreover, there were important differences in the way the war was fought in the West. First of all, the western theater was simply much larger. In the East, which contained both of the national capitals, most of the headline-grabbing battles took place in an area bounded by the Allegheny Mountains to the west and the Chesapeake Bay to the east. Gettysburg marked its northern limit and Petersburg its southern. Though it seemed enormous to the soldiers who had to march across it from place to place, it was a relatively small area, roughly the size of Massachusetts. By contrast, the war in the West ebbed and flowed in an area nearly 20 times as large. Given those dimensions, railroads were critical. Confederate General Braxton Bragg moved his army over 1,000 miles by rail to outflank a Union army in 1862; James Longstreet took two divisions across five states by rail to reinforce the Confederate army on the eve of Chickamauga in 1863; and Joseph E. Johnston and William T. Sherman fought an entire campaign over control of the Western & Atlantic Railroad in 1864 in what may have been the decisive campaign of the war.

Even more critical, however, were the rivers. The rivers in the West were essential not only to the movement of armies, but also to the transport of the supplies necessary to sustain those armies. Transport ships could carry more men and goods, and do so more quickly and efficiently than railroads. And while rampaging cavalry might be able to interrupt railroad traffic by tearing up rails and burning bridges, they could not stop the flow of the rivers. Of course, transports could be ambushed by parties on shore, such as the battery the rebels briefly established at Commerce, Missouri, and for that reason, gunboats were necessary to escort the transports and keep the rivers secure.

In addition, the rivers were geographical realities that affected the strategic planning of both sides. In the East, where the main field armies of both sides slugged it out between Richmond and Washington, the rivers ran mostly west to east—that is horizontally as they appear on a map—athwart any potential Union line of advance, making them defensive barriers that worked to the South's advantage. Civil War scholar Daniel Sutherland has named the Rappahannock-Rapidan River line in Virginia the "dare mark" beyond which Union armies advanced only at their peril. But with the exception of the Ohio River, the principal rivers in the West ran either north-to-south, like the Mississippi, or south-to-north, like the Cumberland and Tennessee Rivers—that is, vertically as they appear on a map. Consequently they served not as barriers to a Union attack, but as avenues along which Union armies, supported by river gunboats, could advance. For these reasons, Union planners began to consider a river gunboat flotilla from almost the first days of the war.