This thesis examines evidence of earthfast structures at five Coles Creek sites: Baptiste (16Av25), Gordon (22Je501), Greenhouse (16Av2), Nick Farm (16Av22), and St. Gabriel (16Iv128). Using image analysis techniques to take measurements from site maps, structures at each site are examined and likely construction methods are determined. This information, along with the greater context of the structures, is used to determine the functions of the Coles Creek buildings. Large enclosures and smaller shrines provide evidence for ritual activity on premound surfaces. Residences appear to feature both circular and rectangular structures, perhaps serving as seasonal dwellings. Mound summits do not seem to have held residences and many mound-top post features may not have been associated with roofed structures and instead may represent light construction and ritual post-setting.