By around 1550, the community associated with Omussee Creek Mound was definitely in decline, though the exact date of its abandonment is unknown. Many believe this decline was part of a broader regional depopulation caused largely by diseases introduced into the Southeast by European explorers, including Hernando De Soto, who traveled through parts of Alabama and Georgia in the 1540s, while other Europeans were active along the Southeastern coasts soon afterward. The historic Creek tribe traces its origins to the coming together of small, scattered native groups displaced during this era, and by the late 1600s it had emerged as a culturally and politically distinct nation of several allied groups spread across Alabama and Georgia. Modern Houston County lay at the southern edge of this homeland, and Creeks today recognize the Mississippian period residents of this area as among their ancestors. Omussee Creek Mound was built through enormous labor, with basketfuls of earth placed by teams of workers over generations, and archaeology shows that it grew in four distinct phases, each with an earthen base, a clay cap, and a surrounding wooden wall. Structures likely stood atop each stage, although their exact size and purpose remain unknown. At Mississippian mound centers, buildings on mounds were often ceremonially burned or torn down and replaced, sometimes after the death of a chieftain, and although similar customs are presumed for Omussee, much about the mound and its use remains unknown.