From the outset of the Civil War, the importance of the Mississippi River as a line of supply and communications and a military operations corridor was apparent to all on both sides of the Mason–Dixon line. Although “too thick to drink and too thin to plow,” the Mississippi River was regarded as the “spinal column of America.” For more than 2,000 miles the river flows silently on its course to the sea providing a natural artery of commerce. The Mississippi River and its tributaries were the interstate highways of the nineteenth century. These streams drain half the continent and gliding gracefully along their waters steamers, flatboats, and vessels of all descriptions heavily laden with the rich agricultural produce of the land moved downstream to New Orleans en route to world markets. Indeed, the sheer volume of traffic on the Mississippi and tonnage of goods it carried evidenced that the silent water of the mighty river was the single most important economic feature of the continent, the very lifeblood of America. One contemporary wrote emphatically that “The Valley of the Mississippi is America.”