We describe a method for locating the denser, or more cohesive, parts of networks. The method starts from the identification of cliques, or maximal complete subgraphs. Since there are numerous such subgraphs in most networks, they are then aggregated when they overlap sufficiently. The resulting aggregated subgraphs are frequently large, not necessarily disjoint, and comparatively denser regions of the full network; frequently, they have the characteristics of social circles. Applied to an interaction network containing nearly 900 individuals from the American Leadership Study, we identify a number of these denser regions, most of which are small cliques, based on the shared interests and institutional locations of their members. One large central circle also results, and we discuss its interpretation in terms of integration of the overall network.
