The lowland Paraíso Basin of El Salvador, which was investigated by the Cerrón Grande Archaeological Salvage Project, supported considerable agricultural populations from at least the late Middle Preclassic to the Early Postclassic, with a population decline during the Early Classic. The cultural sequence of the basin differs substantially from that of the nearby SE Maya highlands, especially during the Preclassic, even though large-scale events (e.g., Ilopango eruption, Pipil migrations) had similar impacts in both regions. Differences in ceramic and lithic technology are correlated with environmental variation and probable differences in subsistence strategy between the two regions.