X-rays traversing a material deposit charge near an interface between two different materials. Results of measurement and calculation of these charge distributions are presented. The measurements were made using a planar dielectric-filled Faraday cup. The charge was calculated using primarily the Compton and photoelectric effects, experimental electron ranges, and experimental electron reflection coefficients. The charge distributions near the interface were determined for the Compton, photoelectric, and mixed Compton-photoelectric regimes: for each of these, the x-ray direction was from low to high atomic number and also in the opposite direction.