Structure within dense random packed monodisperse spheres is analysed with the aid of CT scans and Discrete Element Models (DEM). CT scans were taken of four physical packings of 6 mm glass beads in various diameter cylindrical containers. Using a technique based on optimisation, spherical particles were fitted to these CT scans and the resulting assemblies were examined in terms of the structures present. These assemblies were also compared to the results of DEM simulations for the purposes of validation. A great deal of structure was found in these systems close to the boundaries. In terms of the radial distribution function. this structure closely resembled a simple two-dimensional ordered packing. It was concluded that this simple structure persisted some distance into the assemblies. (C) 2011 Elsevier B.V. All rights reserved.