MAP 9.5 The Nation’s Major Cities, 1840
By 1840, the United States boasted three major conglomerations of cities. The long-settled ports on the Atlantic — from Boston to Baltimore — served as centers for import merchants, banks, insurance companies, and manufacturers of ready-made clothing, and their financial reach extended far into the interior — nationwide in the case of New York City. A second group of cities stretched along the Great Lakes and included the commercial hubs of Buffalo, Detroit, and Chicago, as well as the manufacturing center of Cleveland. A third urban system extended along the Ohio River, comprising the industrial cities of Pittsburgh and Cincinnati and the wholesale centers of Louisville and St. Louis.