Abstract: Exposure and quantification of radioactivity has become environmental and civil problems around the world. The radioactivity even in minor quantities will build up in human body and subsequently, lead to unknown and erratic health complications particularly those related to sustainable development, agricultural production, habitat, ecosystem, and forest. A very high intrinsic anomalous radioactivity >26 microGy/h was identified in the hinterlands within the boulders of syenite rock body around Puttetti in western part of Kanyakumari district, southern Tamil Nadu, India. Further, in the hinterlands, the weathered rocks around Inayam and Midalam localities were also found to be more radioactive ranging from 4 to 22 microGy/h compared to the radiation exposure from the adjoining beach sectors at various locations from Chavara to Tuticorin (1–14 microGy/h). The observed radiation levels are presumably the highest concentration in southern India and conceivably it is foremost instant that a very high intrinsic radiogenic source in the hinterlands is reported in southwest coast of India. Public concerns of radiation exposure of safety in high background areas are of great social and civil relevance. The construction materials used for dwelling purposes from these areas should be avoided from health hazard point of views. Significant radiation doses will certainly enter the human body as most of the people have the habit of sitting and sleeping on the floor. People living in the region are expected to receive significant radiation, which may get accumulated in the human body causing long-term health problem. It is also advisable if the area falls having already natural background radiation hazard must be avoided for the future nuclear power plants/reactors.