How Philadelphia merchants forged trade networks that fueled America's westward expansion.Finalist for 2026 Hagley Prize in Business History from the Hagley Museum and Library and the Business History ConferenceWhy did the Midwest become part of the United States instead of remaining under English, Spanish, or Native control? In Philadelphia Merchants on Western Waters, historian Kim M. Gruenwald reveals commerce and trade, rather than war and political conflict, as the driving force behind America's westward expansion. Through meticulous research into business records, Gruenwald brings to life the daring ventures of Philadelphia merchant companies like Baynton, Wharton & Morgan, who sought to dominate the Illinois fur trade, and Reed & Forde, who expanded trade routes while speculating in land warrants. Their efforts laid the foundation for the Louisiana Purchase in 1803, which unified both banks of the Ohio and Mississippi Rivers under one nation and set the stage for America's continental empire. Studying international dealings with French, Spanish, and Native powers, as well as the complexities of river commerce, Gruenwald paints a vivid portrait of a transformative era between the colonial Atlantic world and America's westward push to the Pacific. Commercial expansion into what Gruenwald dubs "the Riverine West" represents a unique era in American history between the Atlantic of the colonial British Empire and the overland journeys of Americans heading across the Great Plains to California and Oregon in the nineteenth century. This book redefines our understanding of how a fledgling republic secured control of its western frontier—not through military conquest but through entrepreneurial spirit.
