Bioarchaeological analysis of the MDM site (8DA11) in Miami, Florida (ad 400–1200) has identified human skeletal remains with lesions suggestive of and consistent with treponematosis. A population and epidemiological approach was utilised to compare the MDM site to geographically neighbouring skeletal samples from the Highland Beach mound (8PB11) (ad 600–1200) and Fort Center (8GL12) (ad 1–500/1000). These samples were then integrated with data from previous research on proliferative skeletal lesion prevalence on the Gulf Coast of Florida. Population comparisons suggest a higher prevalence of proliferative skeletal lesions in Atlantic coastal populations as opposed to the nearest sampled site from the interior (p < 0.00001), a trend seemingly different from Gulf Coast populations. This investigation details the presence of treponemal disease in the Everglades archaeological region likely as early as ad 400, and the southern terminus in the contiguous United States that treponematosis has been reported. Copyright © 2013 John Wiley & Sons, Ltd.