Intersite and intrasite settlement patterns in the Lower Papaloapan River Basin, Veracruz, Mexico, provide the basis for a descriptive model of habitation location in estuarine deltaic swamps in Mesoamerica. The model considers environmental and ecological factors that shaped some aspects of settlement patterns. Data used in the study include distributions of prehistoric sites as revealed through examination of aerial photographs as well as though field survey, 19th century occupations and recent rural habitations.