the processes used to produce manufactured gas for heating, cooking and lighting purposes in north america from the early 1800s to the mid-1900s have generated by- products such as coal tar containing monocyclic aromatic hydrocarbons (mahs) and polycyclic aromatic hydrocarbons (pahs), coke, light oil derivatives, and ammonia. improper disposal of these wastes has resulted in contaminated soils, groundwater and sediments at these sites, potentially affecting human health and the environment. there is an increasing reliance on using numerical groundwater modeling to predict fate and transport of contaminants as well as employing predictive simulations to anticipate concentrations of contaminants in groundwater in order to evaluate a remedial action. to this end, developing a visual modflow-based model to simulate groundwater flow and transport of selected mah and pah compounds at a former mgp site located in the midwestern u.s. is the main goal of this study. available site data were compiled to develop the conceptual site model to assess contaminant fluxes and field-scale attenuation rates and to calibrate the groundwater flow model using winpest as a finishing step.