Mercantile activity across the upper Mississippi valley developed from the predisposition of settlers toward market farming. Before outsiders began to establish towns with mercantile activity in mind, barter and peddling activity had spread across the southern part of the region. At first, bartering developed because different farmers, having different skills, were unable or unwilling to maintain a self-sufficient existence. Those unable to meet their needs in one area sought out those able to produce more than they needed, and offered something they produced well, which the other farmer needed, in return. As barter activity increased, one or two farmers inevitably perceived the advantages of someone acting as a middleman between the various household demand and supply curves in the neighborhood. Soon thereafter, one of these prototype merchants relocated at some central site and thus established the beginnings of the town market.

Yet most of these local merchants remained isolated from the outside. Therefore, peddlers, perceiving the rising demand for goods, began to move through the region selling those goods that the locals could not make themselves: fine cloth, pots and pans, chinaware, sewing materials, belts and buckles, buttons, brooms, cordage, furniture, and, of course, clocks. By one account, the roads of southern Illinois were full of peddlers during the 1820s. We also know that peddlers out of Cincinnati continued to ply between river wharfs along the Ohio until after 1830. A similar peddling barge did business between St. Louis and the lower rapids, stopping at ports in between, during the 1820s. But it was not until a permanent merchant arrived that the reciprocal relationship developed between agricultura and urban development.