Much like the rest of America during the mid-nineteenth-century, San Diego, California was in the midst of a transformative period that altered the landscape of the region and the course of the city's history. Through an analysis of a set of primary sources, like store ledgers, local newspapers, and hide and tallow ship manifests and ledgers, this thesis examines how the consumption of materials goods is a reflection of economic, political, social, and cultural issues in San Diego from the 1840s to 1870. By statistically analyzing this set of primary sources, this paper addresses issues during this period such as how consumer patterns of consumption parallel the state of the local economy, the reflection of social and cultural values in consumer purchases, how certain factors influenced what types of goods consumers purchased, and the cultural Americanization of San Diegans. Additionally, issues such as race, gender, cultural dissemination, and the development of the local economy and business community are addressed as well. Through the analysis of these primary sources, this thesis reveals that from the 1840s to 1870, prior to the Horton period of San Diego's history, San Diego underwent a transformation that impacted specific social and cultural facets of material life of San Diego. As California experienced rapid economic, social, and cultural changes during the mid-nineteenth-century, San Diegans consumption of goods paralleled these changes and serve as a reflection how these events impacted the city on a micro-level. Through their consumption of imported material goods San Diegans became increasingly assimilated into the American mainstream as they obtained American industrial and consumer tastes. Through an analysis of patterns of consumption, this research will demonstrate that even peripheral regions of the American frontier were impacted by social, cultural, political, and economic changes that were occurring throughout the United States. Furthermore, through an analysis of consumer patterns of consumption it is possible to examine that ways in which consumerism in San Diego parallels and diverges from the historiography of nineteenth-century American consumerism. In addition to this, this research adds the historiography of San Diego by providing insight into the city's economic progression and growth of its business community. Furthermore, this thesis provides historians with a better understanding of everyday consumerism on the California frontier during the mid-nineteenth-century.