In 1998 the U.S. Forest Service, the U.S. Geological Survey, and the National Park Service formed the Collaborative Environmental Monitoring and Research Initiative (CEMRI) to test strategies for integrated environmental monitoring among the agencies. The initiative combined monitoring and research efforts of the participating Federal programs to evaluate health and sustainability of forest and freshwater aquatic systems in the Delaware River Basin. Forest ecosystem health issues addressed by the CEMRI effort include urbanization and forest fragmentation, productivity and carbon sequestration, nitrogen saturation and calcium depletion, vulnerability to exotic insects, and the effects of interactions among these factors. Ongoing monitoring programs were enhanced with supplemental sampling locations and measurements, and models were developed or modified to associate intensive process-level information with extensive landscape-scale information from satellite, aerial, and ground monitoring systems. The CEMRI project illustrates a powerful approach for integrated tracking of environmental conditions, development of models for predicting responses of forest and aquatic processes to perturbations, estimation of future forest conditions, and identification of threats to watershed health and forest sustainability. This paper discusses the development of the CEMRI in the DRB and methods to address environmental issues across multiple spatial and temporal scales.