This dissertation examines the impact of the Civil War on the rise of industrial capitalism in Cincinnati, Ohio. In an era of laissez faire capitalism, merchants developed economic institutions fitting their circumstances, the most important of which was its Chamber of Commerce and Merchants' Exchange. By 1850, the Chamber controlled much of the city's trade, substantially reducing the risk of conducting business. Although manufacturing had been important throughout the city's short history and grew increasingly more important as time passed, merchants dominated the local economy. The Civil War changed the basis for local prosperity. War ended the Southern trade, throwing the city into a severe financial panic, which convinced many citizens that the Democratic principles of free trade, private capital, small government, and peace remained valid. Within months, however, it became clear to the mercantile elite that wartime prosperity would come only from aligning local self-interest with those of the federal government. The Chamber quickly wed itself to the Lincoln administration and its economic program of protected trade, organized capital, free labor, and a preserved Union. Other elements within the local economy were not so quick to support such a radical transformation. Over the next year and a half Cincinnatians experienced serious social conflict in the form of worker protest, a violent race riot, and a brief threat of Confederate invasion known as the siege of Cincinnati. In the wake of this conflict, renewed prosperity convinced a majority of citizens that they could prosper under the Republican system, thanks to government supply contracts, military success, a national banking system, and the creation of a mythology that touted the city's service to the Union. By 1865, industry had superseded commerce as the city's most important economic activity, and most citizens supported a Republican economic program consistent with that transformation. No longer the center of the West, the city now prospered as a regional center of manufacturing in a national economy.