Abstract In light of the burgeoning literature in whole, goal-directed networks for managing wicked problems in public management, it is timely to examine the theoretical evolution that has both shaped and constrained our understanding of these networks. In this article, we argue that contemporary study of whole networks has been dominated by an internal theoretical lens aimed at understanding how internal characteristics influence network functioning and effectiveness. This perspective assumes networks operate in differentiated environments rather than emphasizing interdependence as part of a broader ecology—networks of networks. In this article, we draw from population ecology to introduce the concept of network domains and offer evidence drawn from a population of 60 health-oriented networks in three counties to illustrate domain level characteristics. Using an inductive mode of theorizing, we leverage insights from these domains to consider population dynamics and pose propositions for advancing a program of study into domain level characteristics that may shape and constrain whole networks and their members.