The lower Gangetic Plain in West Bengal, India, has previously been reported to have groundwater fluoride (F − ) contamination and its hazard; however, more information was needed about the precise location of contamination. The current study highlighted these knowledge gaps covering the toxicity of F − through groundwater by emphasizing the role of hydrogeochemical attributions in F − mobilization, people's socioeconomic behavior, and assessing the possible health risks of the local population. Approximately, 10% of groundwater samples exceeded the recommended value of F − with a moderate contamination factor. The groundwater is highly saline (Na−Cl type) in nature. The intermediate zone between the area of 'rock dominance' and 'precipitation dominance' controlled the leaching of F − from host silicate minerals to groundwater. The saturation index established geogenic activity as the responsible factor and found silicate weathering mineral muscovite for F − leaching in groundwater. The average utility cost for 20 L of safe drinking water was US$ 7.58 per month from affordable households. Total hazard quotient (THQ) was observed maximum for infants and significant ingestion rate (IR), body weight (BW), and body surface area (SA) were the responsible factors for the studied age groups. Fluoride-safe drinking water supply strategies are a necessary step in the studied area.