Background: Human is exposed to radiation in their environment with or without their consent and the exposure to natural background radiation is an unpreventable event on earth. Materials and Methods: An in situ assessment of the indoor and outdoor background radiation in Akwanga and Keffi towns of Nasarawa state Nigeria was carried out using a halogen-quenched Geiger Muller (GM) detector (Inspector alert Nuclear radiation monitor SN: 3544). Each of these towns was divided into at least 20 sampling areas where at least ten readings were taken in order to have a reliable data. Results: The mean indoor and outdoor annual effective dose of Akwanga were 1.29± 0.13mSv/yr and 0.31±0.04 mSv/yr respectively and that of Keffi were 1.08± 0.15mSv/yr and 0.25±0.04 mSv/yr respectively. The radiation levels in both highly populated towns were found to be within the safe limit for areas of normal background set by UNSCEAR (2.4 mSv/yr). Conclusion: These results would serve as a baseline upon which other exposures would be assessed and in the future, serve as reference for dosimetry and decontamination in situations of radiation poisoning of these towns.