The Foley Square Courthouse was designed by Supreme Court architect, Cass Gilbert, in the 1920’s to occupy reclaimed marshland near the southern tip of Manhattan Island. The General Services Administration selected our firm to review the Courthouse and evaluate the building’s response during an earthquake from the perspective of life safety. Since the forces prescribed in Building Codes are inappropriate for the evaluation of existing buildings, we used a site-specific seismic hazard analysis to establish the level of ground shaking for the evaluation. Earthquakes in the Eastern United States occur with far less frequency but sometimes with greater intensity than those in the Western United States. This required that careful attention be paid to the probabilistic description of the ground motion. Based on our analysis, considering the stiffness of the granite clad structure and its masonry infill coupled with the existing wind bracing, we concluded that the building possessed sufficient strength to resist the applied loads. Evaluation of the site soils suggested the potential for liquefaction during large earthquakes and a number of mitigation measures were presented. Nonstructural hazards were also addressed in the study with recommendations to mitigate these hazards presented as a series of prioritized recommendations.