This article compares and contrasts communal and individual properties to examine the relationship between state efforts to formalize property rights and tenure security. The article draws on a study of four landscape mosaics in the Peruvian and Ecuadoran Amazon, selected to represent dynamic forest frontiers. Though Hernando de Soto and other theorists from the property rights school emphasize private individual behavior and land allocation in many collective communities, this research also found collective behavior and land allocation in many individualized communities. The importance of the collective and social relations for both types of properties was particularly salient in the sources of tenure security identified. Though title was one important source, this was insufficient, and often formalization was found to be impermanent. Both groups also emphasized social networks and community relations, on the one hand, and demonstrated use, which further establishes the legitimacy of claims with neighbors, on the other.