A unique data base of stereo-PIV velocity measurements has been recorded and analyzed in order to understand the complex flow separation patterns that occur due to a threedimensional shock-boundary layer interaction (SBLI) within a rectangular inlet. The database will be used for the Second Workshop of CFD predictions of SBLI. This dataset provides the first complete measurements of a three-dimensional SBLI-that is, all three velocity components were measured in all three orthogonal planes (a total of 16 data planes total). An experimental methodology was followed such that the data collected would be of maximum utility for CFD comparisons. These metrics include velocity contours that define the free stream core, the characteristic sonic line and the sizes of corner vortices. The purpose of this paper is to provide methodology and results from the boundary conditions and geometry of the experiment; a later paper will provide the full experimental findings. Access to a website containing the CAD drawings of the experiment, calculations of the metrics of interest, and other information for potential participants in the workshop is