It is known that galaxies like to reside in groups and clusters. Our Galaxy together with Andromeda galaxy and many less massive and dwarf galaxies form the Local group. This galaxy group is located on the periphery of probably non-virializied Local Supercluster which consist of two main clusters Virgo and Fornax and many less populated galaxy groups (Tully 1982, Makarov & Karachentsev 2012). Geller and Huchra in their classical work, Mapping the Universe (1989), found that on scales of the order of 300 mega parsecs (size of rich cluster or supercluster) the Universe is almost uniform. It consists of clusters, walls and filaments separated by large areas which are free of galaxies (cosmic voids).
The distribution and evolution of matter in the Universe are widely studied using computer simulations of the Large Scale Structure in different cosmological times. See for example the results of Millenium Simulations and the NCSA simulations.