St. Tammany Parish, Louisiana, is known as a white suburb of New Orleans. It also has a well-known history as a health resort for wealthy New Orleanians during the summer months, particularly during yellow fever outbreaks in the late nineteenth- and early twentieth centuries. This research investigates the historical geography of this parish in terms of race and attempts to answer the question of how St. Tammany became an attractive place for the development of white subdivisions in the 1950s. I uncover the connections between race, labor, the environment, and political culture of the parish from 1878—the year Reconstruction ended—to 1956, the year of the construction of the Lake Pontchartrain Causeway. Using archival materials, local government documents, and federal census schedules, I show that until the 1940s, St. Tammany Parish had a significant Black population comprising one-third of the total population and concentrated in the southern wards of the parish. After 1878, agriculture became closely tied with a white racial identity within the parish; the lumber, brick manufacturing, and shipbuilding industries became associated with Black racial identities. Perceptions of the environment as healthful and restorative helped establish a health and resort industry on the North Shore, the benefits of which were reserved for whites. These economic and environmental connections to racial identity depended on the legal and political definitions of people of African descent as “Black,” and whites enforced racial divisions with political maneuvers, violence, and access to educational opportunities.