From Life on the Mississippi: An Epic American Adventure, by Rinker Buck (Avid Reader Press / Simon & Schuster, 2022), Kindle pp. 4-5:
During the early decades of the 19th century, the massive flatboat traffic drifting down the Ohio and the Mississippi established the westward drive and political outlook that eventually allowed America to straddle the continent from the Atlantic to the Pacific. This riverine movement began a half century before the more celebrated era of the “pioneers” crossing the western plains in covered wagons in the 1850s. The inland rivers—not the wagon ruts crossing from Missouri to Oregon—were America’s first western frontier. The rivers also carried a much larger migration. During the first five decades of the 19th century, more than three million migrants ventured down the Ohio and Mississippi river valleys to the swelling southwestern frontier. In the 1840s and 1850s, a comparative trickle—fewer than 500,000 travelers—crossed the plains west of the Missouri River by overland routes, primarily the Oregon and California trails. Still, the dusty journey via covered wagon remains the dominant image of America’s westward spread, a classic instance of popular myth prevailing over fact.
Compared to its trading rivals in Europe and the West Indies, America in the early 19th century was what we would call today a developing country, and the economic impact of the internal river trade was staggering. Economic historian Isaac Lippincott compiled statistics that showed that the commercial receipts for river cargo in New Orleans totaled $22 million in 1830, or about $660 million in today’s dollars. By 1840, the New Orleans river trade—swelled by the enormous growth in cotton exports—had increased to almost $50 million. By the Civil War, the cargo moving south through New Orleans was valued at $200 million, or $6 billion today. Lippincott estimates that, meanwhile, “inland river commerce” hubs like St. Louis, Cincinnati, and Natchez, Mississippi, were also trading cargo valued at $200 million or more by the Civil War. Like the Nile, the Thames, or the Seine before them, the western rivers in America became a floating supply chain that fueled national growth.