Iron production represents amajor technological shift in African prehistory, and a growing body of archaeological and archaeometric data over the past few decades testifies to the complex origins and development of this technology across West Africa. The recent discovery and excavation of four iron smelting sites in the Falémé River region in eastern Senegal (Dakaba, Birandjikou, Madina Cheikh Oumar 1, and Madina Cheikh Oumar 2) contribute significant detail to this picture, particularly from the fourth century BC to the seventh century AD. The study of the spatial organization of the smelting sites, the furnace architecture, and the morphology of the waste materials reveal the existence of three distinct smelting traditions. The characterization of these specific techniques has been made possible by the archaeometric study of the slag, tuyeres, and ore by means of optical microscopy, XRF, XRD, and thermo-gravimetry. By expanding on the modest body of data for iron metallurgy, the study of these four sites offers new reflections on the evolution of ancient iron smelting technologies in Senegal and across West Africa more widely. These results help to better understand the dynamics of techniques and lifestyles in this part of the continent before the emergence of the first states.