A cultural revolution accompanied the economic transformation of the late 1840s. No longer a small frontier trading post, St. Louis became, almost overnight, a major urban center with big-city problems. The population surged; housing and municipal institutions became inadequate; criminals flocked to St. Louis to tap its wealthy newcomers; disease decimated the residents; and the extraordinary pace of growth created a political and cultural vacuum in the city. Like San Francisco and other western boomtowns, St. Louis was in flux, and residents struggled to stabilize society and to shape its development. The architects of the city's economic rebirth, however, also stood at the center of the city's cultural rebirth.

Yankee influence in the urban West extended beyond the marketplace. As migrants left the Atlantic coast and moved westward, they introduced Yankee culture throughout the Ohio and the Mississippi valleys. Newcomers from the the Northeast brought New York fashions, Boston cultural conventions, Philadelphia institutions, and Yankee “isms” to every city and town in the region. Migration entailed the self-conscious extension of culture as well as the extension of commercial networks, and eastern merchants attempted to mold western cities in the images of New York, Boston, and Philadelphia.

Only a small group of Yankees settled in St. Louis during the late 1840s, though these newcomers assumed a particularly prominent role in the city's development.