Non-invasive geophysical survey was utilized as a remote sensing tool at two prehistoric and two historic sites in California. The sites were investigated with Ground Penetrating Radar (GPR) to identify anomalous signals (targets) which might correspond with subsurface archaeological features. Results of GPR testing at SOL-356 are presented in detail discussing depth of penetration, identification of targets, and the feasibility of future use of GPR technology in cultural resource studies.