The paper provides new data on the age and formation processes of Garba I (Melka Kunture, Upper Awash, Ethiopia). The site, one of the largest handaxe accumulations of the African Acheulean, was extensively excavated in the 1960s of the last century by J. Chavaillon but left largely unpublished. The chronology was also poorly constricted. Quartz grains dated through electron spin resonance (ESR) spectrometry now provide a minimum age of 538 ka for the archaeological layer. In addition, we make available new data allowing an updated interpretation of the stratigraphic sequence and spatial distribution, as well as a detailed taphonomic study of the lithic assemblage. Additional information on the archaeozoological and palaeobotanical record are integrated in the discussion. We conclude that the extensive accumulation of large cuttings tools (LCTs) is not the result of major sedimentary disturbance processes but rather the outcome of a distinct hominin behaviour, which possibly was not focused on the processing and consumption of large mammals. New research at Garba I allows new insights on the Acheulean sites with similar large accumulations of handaxes. Additionally, it contributes to a better understanding of the early Middle Pleistocene in Africa, an under-researched period of the Early Stone Age.