A novel framework for the description of thermodynamic and correlation properties in a dense one‐component plasma (OCP) is presented in a representation based on an ensemble of Coulomb clusters. The properties of spherical and nonspherical Coulomb clusters with number of particlesNin the ground state as well as in a thermally excited state are investigated forN=2–13 by computer simulations. It is shown that a Coulomb cluster with a magic‐number structure, such as an octahedron atN=6 and an icosahedron atN=12, is conspicuously stable even near to the melting temperature of a bulk OCP. Thermodynamic states of the OCP in such a Coulomb‐cluster model are obtained by minimizing the model free energy with respect to fractional population of the clusters with different sizes. In light of such a cluster‐model description, we investigate the issues of cluster formation and possible local order in a dense Coulomb matter. © 1995American Institute of Physics