This chapter examines Formative settlement patterns in two contrasting environmental regions in Mesoamerica, the Valley of Mexico and the southern Veracruz-Tabasco lowlands. It investigates a means by which to describe site distribution so that the applicability of a given model can be tested in an archeological case. The Valley of Mexico has been the object of intensive archeological survey, starting with the Teotihuacan area and moving southward into the regions of Texcoco, Ixtapalapa, and Chaleo. In contrast to the Valley of Mexico, the Olmec region has been subjected to only one intensive and systematic published survey, that of Edward Sisson. The chapter considers briefly the methodology used, its strengths and its shortcomings, and the theoretical framework in which the results are to be interpreted and attempts to reconstruct the structural and functional relationships between Formative communities of different size and complexity.