Mechanical properties of a polymer matrix composite (PMC) are driven by the local interphase properties. Atomic Force Microscopy (AFM), using the technique of Peak Force Quantitative Mechanical Nanomechanical Mapping (PF QNM), was utilized to analyze Young’s modulus, adhesion, and topography at different depths of a PMC at the nanoscale. Dynamic Mechanical Analysis testing was completed for a comparison of the PMC properties at the macroscale. This research shows the evolution of through-thickness interphase properties at the subsurface and at the middle of an epoxy resin composite material. The extent of adhesion and cohesion damage affect the local interphase properties.