Settled in 1565 by the Pedro Menéndez de Aviles expedition, St. Augustine, Florida, holds great educational, historical, and anthropological interest for current researchers as the oldest continuously occupied European community in the continental United States. Archaeological excavations produced two large (ca. 20 cm diameter) posts from the Fountain of Youth Archaeological Park site. Our objective in this project was to use tree-ring dating to determine the outermost dates of the two posts and to use these dates to assist archaeological interpretations. Sample 8SJ31-2741 was pine and contained tree rings that were successfully crossdated using the Lake Louise reference chronology from southern Georgia to AD 1620–1668. Sample 8SJ31-2766 was a cypress sample that we could not crossdate using a nearby reference chronology from the Altamaha River in southern Georgia. The date for sample 8SJ31-2741 places its cutting and deposition within the Mission Period occupation and verifies that the Nombre de Dios mission village was still active and building after 1668 into the late 17th Century. Furthermore, the dendrochronological date confirmed the stratigraphic interpretation, suggesting that disturbance of the upper layers of the surface in this part of the site was perhaps not as disruptive to the soils as originally assumed. This project demonstrates the feasibility of dating wood extracted from sites from the historic Spanish-era period in the Southeastern US.