Fertilizer application is essential for agricultural productivity but can pose significant risks to soil and groundwater quality when mismanaged. This study employed twodimensional Electrical Resistivity Tomography (2D ERT) to assess fertilizer-related contamination in selected upland and lowland farmlands in Oghara, Delta State, Nigeria. Field data were acquired using the Wenner array configuration of the ABEM Terrameter SAS 300C, with a 10 m electrode spacing and profile lengths of 100–140 m. Data processing and inversion were carried out using RES2DINV software.