Most of the materials used in landfill liners are not based on the local soil conditions which increases the cost of landfill construction. It is needed to develop a composite mix based on local soil that fulfills the design parameters of the municipal solid waste (MSW) landfill at a reasonable cost as per USEPA 1989 guidelines. The current study investigates the local soil and bentonite mixtures to obtain an optimum composite mix with specific properties of landfill liners. The experimental investigation was conducted on different proportions of local soil–bentonite mixes to evaluate the optimum mix proportion for the liner materials. The curing period of different mixes is also considered. The geotechnical properties like liquid limit, free swell index, and optimum moisture content increased, whereas the maximum dry density and hydraulic conductivity decreased with an increase in bentonite content up to 20% with soil. These mixes are compacted at optimum moisture content and maximum dry density satisfying both plasticity criteria that is liquid limit (LL ≥ 20%) and plasticity index (PI ≥ 7%), and also permeability criteria (k ≤ 1 × 10−7 cm/s) as well as unconfined compressive strength criteria (UCS = 200 kPa).