Groundwater modeling is a proven technology used to support the closure of contaminated sites. Normal applications of this technology include site assessment, remediation design and remediation performance evaluation for a site closure. This document summarizes practical examples of applying groundwater modeling in conjunction with engineering calculations. These examples include a site assessment for an industrial site and remediation design for both an industrial site and a superfund site. At these project sites, only the dissolved-phase contaminants and limited amounts of residual Non-Aqueous Phase Liquids (NAPLs) were present. Based on the objectives of site closure, site characteristics and cost consideration, both analytical and numerical models were used in supporting these site closures. The objectives of site closure included 1) the removal of dissolved-phase contaminants in groundwater to required levels, and 2) at the same time, containment of the plume.