While extensively studied in liquid water, there have been no prior investigations exploring the evolution of ring structures as a means of tracking order during the transition of water into ice. In this study, we identify key ring motifs participating in water crystallization: the populations of singlet and coupled rings involving 5, 6 and 7-member rings increase significantly in the interfacial region relative to the bulk liquid, with those involving of 5 and 7-member rings exhibiting maxima while only those for 6-member rings increase continuously. The configurations and populations of ring motifs facilitate the exploration of potential pathways through which water rings evolve to bulk ice. (C) 2011 Elsevier B.V. All rights reserved.