Monitoring and identifying sources of water contaminants necessitates research into hydro-chemical interactions and the health of groundwater resources. Sixty (n = 60) representative samples of groundwater in Makurdi metropolis were evaluated utilizing hydro-geochemical characterization and GIS methodologies. The region's groundwater quality was planned and monitored using a GIS-based water quality index (WQI). To identify the variance in hydro-geochemical facies and to understand the functional sources of chemical constituents, Piper trilinear and Gibbs diagrams were produced. The test results revealed that the groundwater is very alkaline in nature. For each measure, the majority of the samples fell within the desirable and maximum permissible ranges set by the Nigeria Standard for Drinking Water Quality (NSDWQ). According to the Piper diagram, 86.67% of the samples are of the Na+ - K+ - HCO32− type, indicating alkali carbonate, while 13.33% are of the Na+ - K+ - Cl− - SO42− type, indicating salinity. In 100% of the samples, alkalis outnumber alkaline earth, and weak acid outnumbers strong acid in more than half (86.67%) of the groundwater samples. According to the water quality index (WQI), 93% of locations have excellent or good quality water, whereas 7% of sites have poor quality water. The permitted limits for TH, Na+, Cl, NO3 and SO42 are exceeded by the WQI values. The present investigation indicates significant dominance of agriculture and rock weathering capable of influencing the groundwater chemistry in Makurdi metropolis. Anthropogenic activities which can result in groundwater quality deterioration should be curtailed to avoid widespread of groundwater pollution.