<p>Saldanha Bay on the west coast of South Africa is surrounded by various nature reserves, military units and training sites. Over a long period of time, large parts of this semi-arid area were exposed to human activities, including military training and the preparation of forces for war. This article investigates the prospect of identifying areas where human activities took place via mapping of the variation in primordial radioactive isotopes. For this purpose, <em>in situ</em> gamma-ray data were obtained from selected locations around Saldanha Bay. The data were used to extract concentrations of primordial radioactive isotopes in these locations. The radioactive primordial isotope concentrations were then mapped and compared to historical evidence of human activities in these areas. The concentrations of potassium isotope showed a relationship to the height above mean sea level. Historical human activities were mainly confined to flatter regions of the area around Saldanha Bay and therefore also relate to the height above mean sea level. The potassium concentrations and the areas where human activities took place were compared and a significant relationship was found.</p>