Charleston was a coastal port city on the Atlantic Ocean, and, along with its physical geography, that led to heightened social interaction between slaves, free blacks, and European immigrants. Charleston’s slave population increased between 1820 and 1861, reaching more than seventeen thousand. Slaves lived in residences throughout the city and often in separate living quarters. The free black population also experienced significant population increases during the first half of the nineteenth century. German and Irish immigration also had implications for the social relations of Charleston during the mid-to-late nineteenth century. German and Irish immigrants arrived in large numbers during the 1850s, and they encountered a thriving free black population in Charleston, slightly larger than their own, and thousands of slaves. Moreover, some Germans and Irish who had arrived in the 1830 and early 1840s had socialized to certain white southern norms, including slaveholding. Many immigrants experienced death by migration, because their immune systems did not protect them as well from specific diseases. Health conditions in Charleston endangered immigrants who lived in low-lying, unsanitary places throughout the city. Yellow fever proved particularly deadly to German and Irish immigrants, and more than one thousand died during epidemics between 1849 and 1858.