This paper presents a comprehensive investigation of the slope stability along a 1.28 km segment of the Sanfebagar-Martadi Road in the Bajura district of Nepal, following a major landslide. Landslides, a common natural hazard in mountainous regions, pose significant threats to both life and property. This study integrates Electrical Resistivity Tomography (ERT) with geotechnical investigations to assess slope stability under various conditions—dry, saturated, and seismic—using GeoStudio 2022.1 software. The findings reveal that the slope is critically unstable, with the factor of safety dropping at 0.561 during monsoon seasons. Recommended mitigation measures, including soil nails, micro-piles, concrete riprap, and gabion structures, were evaluated for their effectiveness in enhancing slope stability. The study emphasizes the critical role of detailed geotechnical and geophysical evaluations in developing protective strategies to mitigate future landslides.