Ground penetrating radar (GPR) can be used in appropriate geological settings to help map subsurface geological structures and groundwater contaminants. Associated engineering and environmental applications are numerous. In particular, GPR surveys can help to identify the approximate boundaries of contaminant plumes and provide stratigraphic information at a site. Case studies from sites in Arizona and Utah show that good correlation exists between GPR signatures and hydrocarbon contamination is strategically located wells. GPR data can also be very useful in identifying shallow faulting, and the characteristics of the associated subsurface deformation can be used to gain a better understanding of the potential for surface ruptures at a site. An example from along the Wasatch Fault Zone, Utah County, Utah, shows good correlation between GPR data and trench data. Finally, examples from Provo, Utah and Eureka, Utah demonstrate the utility of using GPR for locating underground excavations and/or cavities.